aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorThomas Albers Raviola <thomas@thomaslabs.org>2024-11-21 15:55:03 +0100
committerThomas Albers Raviola <thomas@thomaslabs.org>2024-11-21 15:55:03 +0100
commit6d4ad089c5b758ad8af4f68bf385a26ec4e9653a (patch)
tree2fd65006b57d646b53e121aef42bba5ee5852840
Initial commit
-rw-r--r--.gitignore1
-rw-r--r--COPYING674
-rw-r--r--Makefile65
-rw-r--r--README.md37
-rw-r--r--asm/crt0.asm64
-rw-r--r--asm/delay.asm13
-rw-r--r--asm/isr.asm17
-rw-r--r--include/fifo.h45
-rw-r--r--include/hardware.h80
-rw-r--r--include/i2c.h24
-rw-r--r--include/input.h22
-rw-r--r--include/tft.h132
-rw-r--r--include/tty.h34
-rw-r--r--include/zeta.h67
-rw-r--r--manifest.scm6
-rw-r--r--src/bootloader.c310
-rw-r--r--src/crc16.c48
-rw-r--r--src/fifo.c0
-rw-r--r--src/font.c101
-rw-r--r--src/i2c.c103
-rw-r--r--src/input.c59
-rw-r--r--src/main.c185
-rw-r--r--src/menu.c269
-rw-r--r--src/tft.c138
-rw-r--r--src/tty.c164
25 files changed, 2658 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a007fea
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/*
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..f288702
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+ The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works. By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users. We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors. You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+ To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights. Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received. You must make sure that they, too, receive
+or can get the source code. And you must show them these terms so they
+know their rights.
+
+ Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+ For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software. For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+ Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so. This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software. The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable. Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products. If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+ Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary. To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ TERMS AND CONDITIONS
+
+ 0. Definitions.
+
+ "This License" refers to version 3 of the GNU General Public License.
+
+ "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+ "The Program" refers to any copyrightable work licensed under this
+License. Each licensee is addressed as "you". "Licensees" and
+"recipients" may be individuals or organizations.
+
+ To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy. The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+ A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+ To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy. Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+ To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies. Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+ An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License. If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+ 1. Source Code.
+
+ The "source code" for a work means the preferred form of the work
+for making modifications to it. "Object code" means any non-source
+form of a work.
+
+ A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+ The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form. A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+ The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities. However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work. For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+ The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+ The Corresponding Source for a work in source code form is that
+same work.
+
+ 2. Basic Permissions.
+
+ All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met. This License explicitly affirms your unlimited
+permission to run the unmodified Program. The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work. This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+ You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force. You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright. Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+ Conveying under any other circumstances is permitted solely under
+the conditions stated below. Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+ 3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+ No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+ When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+ 4. Conveying Verbatim Copies.
+
+ You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+ You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+ 5. Conveying Modified Source Versions.
+
+ You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+ a) The work must carry prominent notices stating that you modified
+ it, and giving a relevant date.
+
+ b) The work must carry prominent notices stating that it is
+ released under this License and any conditions added under section
+ 7. This requirement modifies the requirement in section 4 to
+ "keep intact all notices".
+
+ c) You must license the entire work, as a whole, under this
+ License to anyone who comes into possession of a copy. This
+ License will therefore apply, along with any applicable section 7
+ additional terms, to the whole of the work, and all its parts,
+ regardless of how they are packaged. This License gives no
+ permission to license the work in any other way, but it does not
+ invalidate such permission if you have separately received it.
+
+ d) If the work has interactive user interfaces, each must display
+ Appropriate Legal Notices; however, if the Program has interactive
+ interfaces that do not display Appropriate Legal Notices, your
+ work need not make them do so.
+
+ A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit. Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+ 6. Conveying Non-Source Forms.
+
+ You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+ a) Convey the object code in, or embodied in, a physical product
+ (including a physical distribution medium), accompanied by the
+ Corresponding Source fixed on a durable physical medium
+ customarily used for software interchange.
+
+ b) Convey the object code in, or embodied in, a physical product
+ (including a physical distribution medium), accompanied by a
+ written offer, valid for at least three years and valid for as
+ long as you offer spare parts or customer support for that product
+ model, to give anyone who possesses the object code either (1) a
+ copy of the Corresponding Source for all the software in the
+ product that is covered by this License, on a durable physical
+ medium customarily used for software interchange, for a price no
+ more than your reasonable cost of physically performing this
+ conveying of source, or (2) access to copy the
+ Corresponding Source from a network server at no charge.
+
+ c) Convey individual copies of the object code with a copy of the
+ written offer to provide the Corresponding Source. This
+ alternative is allowed only occasionally and noncommercially, and
+ only if you received the object code with such an offer, in accord
+ with subsection 6b.
+
+ d) Convey the object code by offering access from a designated
+ place (gratis or for a charge), and offer equivalent access to the
+ Corresponding Source in the same way through the same place at no
+ further charge. You need not require recipients to copy the
+ Corresponding Source along with the object code. If the place to
+ copy the object code is a network server, the Corresponding Source
+ may be on a different server (operated by you or a third party)
+ that supports equivalent copying facilities, provided you maintain
+ clear directions next to the object code saying where to find the
+ Corresponding Source. Regardless of what server hosts the
+ Corresponding Source, you remain obligated to ensure that it is
+ available for as long as needed to satisfy these requirements.
+
+ e) Convey the object code using peer-to-peer transmission, provided
+ you inform other peers where the object code and Corresponding
+ Source of the work are being offered to the general public at no
+ charge under subsection 6d.
+
+ A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+ A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling. In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage. For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product. A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+ "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source. The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+ If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information. But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+ The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed. Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+ Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+ 7. Additional Terms.
+
+ "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law. If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+ When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it. (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.) You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+ Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+ a) Disclaiming warranty or limiting liability differently from the
+ terms of sections 15 and 16 of this License; or
+
+ b) Requiring preservation of specified reasonable legal notices or
+ author attributions in that material or in the Appropriate Legal
+ Notices displayed by works containing it; or
+
+ c) Prohibiting misrepresentation of the origin of that material, or
+ requiring that modified versions of such material be marked in
+ reasonable ways as different from the original version; or
+
+ d) Limiting the use for publicity purposes of names of licensors or
+ authors of the material; or
+
+ e) Declining to grant rights under trademark law for use of some
+ trade names, trademarks, or service marks; or
+
+ f) Requiring indemnification of licensors and authors of that
+ material by anyone who conveys the material (or modified versions of
+ it) with contractual assumptions of liability to the recipient, for
+ any liability that these contractual assumptions directly impose on
+ those licensors and authors.
+
+ All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10. If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term. If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+ If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+ Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+ 8. Termination.
+
+ You may not propagate or modify a covered work except as expressly
+provided under this License. Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+ However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+ Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+ Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License. If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+ 9. Acceptance Not Required for Having Copies.
+
+ You are not required to accept this License in order to receive or
+run a copy of the Program. Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance. However,
+nothing other than this License grants you permission to propagate or
+modify any covered work. These actions infringe copyright if you do
+not accept this License. Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+ 10. Automatic Licensing of Downstream Recipients.
+
+ Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License. You are not responsible
+for enforcing compliance by third parties with this License.
+
+ An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations. If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+ You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License. For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+ 11. Patents.
+
+ A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based. The
+work thus licensed is called the contributor's "contributor version".
+
+ A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version. For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+ Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+ In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement). To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+ If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients. "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+ If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+ A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License. You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+ Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+ 12. No Surrender of Others' Freedom.
+
+ If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all. For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work. The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+ 14. Revised Versions of this License.
+
+ The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation. If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+ If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
+permissions. However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ <program> Copyright (C) <year> <name of author>
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..9311c3e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,65 @@
+PROJECT=firmware
+
+AS=sdasz80
+CC=sdcc
+CPP=sdcpp
+
+ASM=crt0.asm\
+ isr.asm\
+ delay.asm
+SRC=crc16.c\
+ bootloader.c\
+ font.c\
+ i2c.c\
+ input.c\
+ main.c\
+ tft.c\
+ tty.c\
+ menu.c
+
+OBJ=$(ASM:%.asm=build/%.rel)\
+ $(SRC:%.c=build/%.rel)
+
+IHX=build/$(PROJECT).ihx
+TARGET=build/$(PROJECT).hex
+
+INCLUDE=include
+CFLAGS=-mz80 -I$(INCLUDE) --Werror
+LDFLAGS=-mz80 --no-std-crt0\
+ --code-loc 0x0100\
+ --data-loc 0x8010\
+ -Wl-b_ISR_TABLE=0x0070\
+ -Wl-b_GSINIT=0x0080
+
+ROM_CHIP=AT28C256
+
+all : $(TARGET)
+
+$(OBJ): | build
+
+build:
+ @mkdir -p build
+
+build/%.rel : asm/%.asm
+ @echo ' (AS)' $<
+ @$(CPP) -P -I$(INCLUDE) -DASSEMBLY $< > build/$(notdir $<)
+ @$(AS) -g -o $@ build/$(notdir $<)
+
+build/%.rel : src/%.c
+ @echo ' (CC)' $<
+ @$(CC) $(CFLAGS) -c -o $@ $<
+
+$(IHX) : $(OBJ)
+ @echo ' (LD)' $(OBJ)
+ @$(CC) $(LDFLAGS) -o $@ $(OBJ)
+
+$(TARGET) : $(IHX)
+ @hex2bin.py $< $@
+
+.PHONE : flash
+flash :
+ @minipro -y -sp $(ROM_CHIP) -w $(TARGET)
+
+.PHONY : clean
+clean :
+ @find build -type f -delete
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..0ef7710
--- /dev/null
+++ b/README.md
@@ -0,0 +1,37 @@
+# Firmware for the Southern Star Mk II
+
+This repository contains the firmware for the Southern Star Mk II. A wearable
+computer built using a Z80 microprocessor.
+
+The code here is *really* early in development. It consists mostly code of code
+fragments from other prototypes held together by duct tape. Almost nothing of
+the architecture and capabilities of the operating system has been decided.
+
+The firmware includes a modified version of the
+[zbootloader](https://git.thomaslabs.org/zbootloader/) for uploading programs
+over the serial port. (see [zup](https://git.thomaslabs.org/zup/), the upload
+utility)
+
+## What is missing?
+
+The question should be, what is not missing? Nonetheless:
+- Documentation on the hardware and software architecture
+- Tests for the bootloader
+- Update ROM contents over USB
+- scheme interpreter and compiler
+- multitasking (if doable in such a restricted environment)
+- Filesystem support
+
+## File structure
+- asm: Assembly code
+- doc: Documentation (not ready yet)
+- include: header files for both C and Assembly
+- src: C source code
+- manifest.scm: Guix packages for compiling the firmware image
+
+## Related repositories
+[Computer schematics](https://git.thomaslabs.org/southern-star-mk2/hardware/)
+[3D Model of the enclosure](https://git.thomaslabs.org/southern-star-mk2/3d/)
+
+## Acknowledgements
+- SDCC developers; Big part of asm/crt0.asm is taken from the defualt crt0 file
diff --git a/asm/crt0.asm b/asm/crt0.asm
new file mode 100644
index 0000000..6f92149
--- /dev/null
+++ b/asm/crt0.asm
@@ -0,0 +1,64 @@
+#include <hardware.h>
+
+ .module crt0
+ .globl _main
+
+ .area _HEADER (ABS)
+ .org 0x0000
+start:
+ xor a
+ ld i, a
+ ld sp, #0x0000
+ di
+
+ call gsinit
+ call _main
+1$:
+ halt
+ jr 1$
+
+ ;; Ordering of segments for the linker.
+ .area _HOME
+ .area _CODE
+ .area _INITIALIZER
+ .area _GSINIT
+ .area _GSFINAL
+
+ .area _DATA
+ .area _INITIALIZED
+ .area _BSEG
+ .area _BSS
+ .area _HEAP
+
+ .area _CODE
+
+ .area _GSINIT
+gsinit:
+ ;; Default-initialized global variables.
+ ld bc, #l__DATA
+ ld a, b
+ or a, c
+ jr Z, zeroed_data
+ ld hl, #s__DATA
+ ld (hl), #0x00
+ dec bc
+ ld a, b
+ or a, c
+ jr Z, zeroed_data
+ ld e, l
+ ld d, h
+ inc de
+ ldir
+zeroed_data:
+ ;; Explicitly initialized global variables.
+ ld bc, #l__INITIALIZER
+ ld a, b
+ or a, c
+ jr Z, gsinit_next
+ ld de, #s__INITIALIZED
+ ld hl, #s__INITIALIZER
+ ldir
+
+gsinit_next:
+ .area _GSFINAL
+ ret
diff --git a/asm/delay.asm b/asm/delay.asm
new file mode 100644
index 0000000..f04f046
--- /dev/null
+++ b/asm/delay.asm
@@ -0,0 +1,13 @@
+ .module delay
+
+__delay_ms::
+ ld b, a
+1$:
+ ld hl, #400
+2$:
+ dec hl
+ ld a, h
+ or l
+ jr nz, 2$
+ djnz 1$
+ ret
diff --git a/asm/isr.asm b/asm/isr.asm
new file mode 100644
index 0000000..ad810e5
--- /dev/null
+++ b/asm/isr.asm
@@ -0,0 +1,17 @@
+ .module isr
+
+ .area _ISR_TABLE (REL)
+_ctc0_isr_ptr::
+ .dw #0
+_ctc1_isr_ptr::
+ .dw #_ctc1_isr
+_ctc2_isr_ptr::
+ .dw #_timer
+_ctc3_isr_ptr::
+ .dw #_blink_cursor
+_port_a_isr_ptr::
+ .dw #0
+_port_b_isr_ptr::
+ .dw #_input_event
+_rx_isr_ptr::
+ .dw #_rx_isr
diff --git a/include/fifo.h b/include/fifo.h
new file mode 100644
index 0000000..c6eee2d
--- /dev/null
+++ b/include/fifo.h
@@ -0,0 +1,45 @@
+#ifndef FIFO_H
+#define FIFO_H
+
+#include <zeta.h>
+
+#define FIFO_LEN 32
+
+struct fifo {
+ uint8_t head;
+ uint8_t tail;
+ uint8_t data[FIFO_LEN];
+};
+
+static inline uint8_t
+fifo_pop(struct fifo *fifo)
+{
+ uint8_t ret = fifo->data[fifo->head];
+ if (++fifo->head >= LENGTH(fifo->data))
+ fifo->head = 0;
+ return ret;
+}
+
+static inline void
+fifo_push(struct fifo *fifo, uint8_t v)
+{
+ fifo->data[fifo->tail] = v;
+
+ if (++fifo->tail >= LENGTH(fifo->data))
+ fifo->tail = 0;
+}
+
+static inline bool
+fifo_empty(const struct fifo *fifo)
+{
+ return (fifo->head == fifo->tail);
+}
+
+static inline void
+fifo_clear(struct fifo *fifo)
+{
+ fifo->head = 0;
+ fifo->tail = 0;
+}
+
+#endif // FIFO_H
diff --git a/include/hardware.h b/include/hardware.h
new file mode 100644
index 0000000..2e6c9da
--- /dev/null
+++ b/include/hardware.h
@@ -0,0 +1,80 @@
+#ifndef HARDWARE_H
+#define HARDWARE_H
+
+// ********************************************************
+#define CTC_CHANNEL_0 0x00
+#define CTC_CHANNEL_1 0x01
+#define CTC_CHANNEL_2 0x02
+#define CTC_CHANNEL_3 0x03
+
+#define CTC_CTRL_OR_VECTOR_BIT 0x01
+#define CTC_RST_BIT 0x02
+#define CTC_TIME_CONST_BIT 0x04
+#define CTC_TIME_TRG_BIT 0x08
+#define CTC_CLK_TRG_BIT 0x10
+#define CTC_PRESCALER_BIT 0x20
+#define CTC_MODE_BIT 0x40
+#define CTC_INT_BIT 0x80
+
+#define CTC_CTRL(x) ((x) | CTC_CTRL_OR_VECTOR_BIT)
+
+// ********************************************************
+#define PORT_A_CTRL 0x42
+#define PORT_A_DATA 0x40
+#define PORT_B_CTRL 0x43
+#define PORT_B_DATA 0x41
+
+#define PIO_MODE_3 0xCF
+
+#define PIO_INT_CTRL(x) ((x) | 0x07)
+#define PIO_OR 0x00
+#define PIO_AND 0x40
+#define PIO_LOW 0x00
+#define PIO_HIGH 0x20
+#define PIO_MASK 0x10
+#define PIO_INT_EN 0x80
+
+// ********************************************************
+#define SIO_A_CTRL 0x22
+#define SIO_A_DATA 0x20
+#define SIO_B_CTRL 0x23
+#define SIO_B_DATA 0x21
+
+#define SIO_EX_INT_EN 0x01
+#define SIO_TX_INT_EN 0x02
+#define SIO_STATUS_AFFECTS_VECTOR 0x04
+#define SIO_RX_INT_MD0 0x08
+#define SIO_RX_INT_MD1 0x10
+#define SIO_WAIT_RDY_ON_RX_TX 0x20
+#define SIO_WAIT_RDY_FTN 0x40
+#define SIO_WAIT_RDY_EN 0x80
+
+// ********************************************************
+#define TFT_CTRL 0x60
+#define TFT_DATA 0x61
+
+#ifndef ASSEMBLY
+__sfr __at(CTC_CHANNEL_0) ctc_channel_0;
+__sfr __at(CTC_CHANNEL_1) ctc_channel_1;
+__sfr __at(CTC_CHANNEL_2) ctc_channel_2;
+__sfr __at(CTC_CHANNEL_3) ctc_channel_3;
+
+__sfr __at(SIO_A_DATA) sio_a_data;
+__sfr __at(SIO_B_DATA) sio_b_data;
+__sfr __at(SIO_A_CTRL) sio_a_ctrl;
+__sfr __at(SIO_B_CTRL) sio_b_ctrl;
+
+__sfr __at(PORT_A_DATA) port_a_data;
+__sfr __at(PORT_B_DATA) port_b_data;
+__sfr __at(PORT_A_CTRL) port_a_ctrl;
+__sfr __at(PORT_B_CTRL) port_b_ctrl;
+
+__sfr __at(TFT_CTRL) tft_ctrl;
+__sfr __at(TFT_DATA) tft_data;
+
+#define IM(__mode) __asm__("im " #__mode)
+#define EI __asm__("ei")
+#define DI __asm__("di")
+#endif // ASSEMBLY
+
+#endif // HARDWARE_H
diff --git a/include/i2c.h b/include/i2c.h
new file mode 100644
index 0000000..18fa5e9
--- /dev/null
+++ b/include/i2c.h
@@ -0,0 +1,24 @@
+#ifndef I2C_H
+#define I2C_H
+
+#include <stdint.h>
+
+#define NACK 0
+#define ACK 1
+
+void
+i2c_start_condition(void);
+
+void
+i2c_restart_condition(void);
+
+void
+i2c_stop_condition(void);
+
+void
+i2c_send(uint8_t b);
+
+uint8_t
+i2c_recv(uint8_t ack);
+
+#endif // I2C_H
diff --git a/include/input.h b/include/input.h
new file mode 100644
index 0000000..a2f03e2
--- /dev/null
+++ b/include/input.h
@@ -0,0 +1,22 @@
+#ifndef INPUT_H
+#define INPUT_H
+
+#include <fifo.h>
+
+static inline uint8_t
+poll_keys(void)
+{
+ return (port_b_data & 0x7C) >> 2;
+}
+
+enum keys {
+ KEY1 = 0x01,
+ KEY2 = 0x02,
+ KEY3 = 0x04,
+ KEY4 = 0x08,
+ KEY5 = 0x10
+};
+
+extern struct fifo input_fifo;
+
+#endif // INPUT_H
diff --git a/include/tft.h b/include/tft.h
new file mode 100644
index 0000000..22303a1
--- /dev/null
+++ b/include/tft.h
@@ -0,0 +1,132 @@
+#ifndef TFT_H
+#define TFT_H
+
+#include <hardware.h>
+#include <stdint.h>
+
+#define TFT_WIDTH 480
+#define TFT_HEIGHT 320
+
+enum tft_command {
+ NOP = 0x00,
+ SWRESET = 0x01,
+ RDDID = 0x04,
+ RDNUMPE = 0x05,
+ RDRED = 0x06,
+ RDGREEN = 0x07,
+ RDBLUE = 0x08,
+ RDDPM = 0x0A,
+ RDDMADCTL = 0x0B,
+ RDDCOLMOD = 0x0C,
+ RDDIM = 0x0D,
+ RDDSM = 0x0E,
+ RDDSDR = 0x0F,
+ SPLIN = 0x10,
+ SLPOUT = 0x11,
+ PTLON = 0x12,
+ NORON = 0x13,
+ INVOFF = 0x20,
+ INVON = 0x21,
+ ALLPOFF = 0x22,
+ ALLPON = 0x23,
+ GAMSET = 0x26,
+ DISPOFF = 0x28,
+ DISPON = 0x29,
+ CASET = 0x2A,
+ PASET = 0x2B,
+ RAMWR = 0x2C,
+ RAMRD = 0x2E,
+ PLTAR = 0x30,
+ VSCRDEF = 0x33,
+ TEOFF = 0x34,
+ TEON = 0x35,
+ MADCTL = 0x36,
+ VSCRSADD = 0x37,
+ IDMOFF = 0x38,
+ IDMON = 0x39,
+ COLMOD = 0x3A,
+ CONRAMWR = 0x3C,
+ CONRAMRD = 0x3E,
+ TESL = 0x44,
+ GETSL = 0x45,
+ WRDISBV = 0x51,
+ RDDISBV = 0x52,
+ WRCTRLD = 0x53,
+ RDCTRLD = 0x54,
+ WRCABC = 0x55,
+ RDCABC = 0x56,
+ WRCABCMB = 0x5E,
+ RDCABCMB = 0x5F,
+ RDABVCSDR = 0x68,
+ RDBWLK = 0x70,
+ RDBKX = 0x71,
+ RDBKY = 0x72,
+ RDWX = 0x73,
+ RDWY = 0x74,
+ RDRGLB = 0x75,
+ RDRX = 0x76,
+ RDRY = 0x77,
+ RDGX = 0x78,
+ RDGY = 0x79,
+ RDBALB = 0x7A,
+ RDBX = 0x7B,
+ RDBY = 0x7C,
+ RDAX = 0x7D,
+ RDAY = 0x7E,
+
+ RDID1 = 0xDA,
+ RDID2 = 0xDB,
+ RDID3 = 0xDC,
+ SETOSC = 0xB0,
+ SETPOWER = 0xB1,
+ SETDISCTRL = 0xB2,
+ SETRGB = 0xB3,
+ SETCYC = 0xB4,
+ SETBGP = 0xB5,
+ SETCOM = 0xB6,
+ SETOTP = 0xB7,
+ SETEXTC = 0xB9,
+ SETSTBA = 0xC0,
+ SETDGC = 0xC1,
+ SETID = 0xC3,
+ SETDDB = 0xC4,
+ SETCABC = 0xC9,
+ SETPANEL = 0xCC,
+ SETGAMMA = 0xE0,
+ SETIMAGE = 0xE9,
+ SETMESSI = 0xEA,
+ SETCOLOR = 0xEB
+};
+
+enum pixel_format {
+ BIT12 = 0x03,
+ BIT16 = 0x05,
+ BIT18 = 0x06,
+ BIT24 = 0x07
+};
+
+static inline void
+tft_ram_wr(void)
+{
+ tft_ctrl = RAMWR;
+}
+
+static inline void
+tft_pixel(uint8_t r, uint8_t g, uint8_t b)
+{
+ tft_data = r;
+ tft_data = g;
+ tft_data = b;
+}
+
+void
+tft_set_area(unsigned int x, unsigned int y, unsigned int w, unsigned int h);
+
+void
+tft_init(void);
+
+void
+clear_screen(void);
+
+
+#endif // TFT_H
diff --git a/include/tty.h b/include/tty.h
new file mode 100644
index 0000000..ea73e5f
--- /dev/null
+++ b/include/tty.h
@@ -0,0 +1,34 @@
+#ifndef TTY_H
+#define TTY_H
+
+#include <tft.h>
+#define TTY_WIDTH (TFT_WIDTH / 8)
+#define TTY_HEIGHT (TFT_HEIGHT / 8)
+
+void
+addch(char c);
+
+void
+addstr(const char *str);
+
+void
+setcur(unsigned int ncol, unsigned int nrow);
+
+void
+swap_colors(void);
+
+static inline void
+mvaddch(int y, int x, char c)
+{
+ setcur(x, y);
+ addch(c);
+}
+
+static inline void
+mvaddstr(int y, int x, const char *str)
+{
+ setcur(x, y);
+ addstr(str);
+}
+
+#endif // TTY_H
diff --git a/include/zeta.h b/include/zeta.h
new file mode 100644
index 0000000..291a2ff
--- /dev/null
+++ b/include/zeta.h
@@ -0,0 +1,67 @@
+#ifndef ZETA_H
+#define ZETA_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef int8_t s8;
+typedef int16_t s16;
+typedef int32_t s32;
+typedef int64_t s64;
+
+typedef uint8_t u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+#define LENGTH(x) (sizeof(x) / sizeof(x[0]))
+#define MAX(x, y) ((x) > (y) ? (x) : (y))
+#define MIN(x, y) ((x) < (y) ? (x) : (y))
+
+// Corrent version, but the compiler does not recognize this as a constant
+// expression
+// #define ISR_ADDRESS(x) (((u16)&x) & 0xFF)
+#define ISR_ADDRESS(x) ((u16)&x)
+
+extern void *rx_isr_ptr;
+extern void *ctc0_isr_ptr;
+extern void *ctc1_isr_ptr;
+extern void *ctc2_isr_ptr;
+extern void *ctc3_isr_ptr;
+extern void *port_a_isr_ptr;
+extern void *port_b_isr_ptr;
+
+void
+bootloader(void);
+
+uint16_t
+crc16(const void *buf, size_t len);
+
+void
+_menu(void);
+
+static inline int
+max(int a, int b)
+{
+ return a > b ? a : b;
+}
+
+static inline int
+min(int a, int b)
+{
+ return a < b ? a : b;
+}
+
+static inline int
+clamp(int v, int low, int high)
+{
+ return min(max(v, low), high);
+}
+
+static inline uint8_t
+bcd(uint8_t x)
+{
+ return ((x / 10) << 4) | (x % 10);
+}
+
+#endif // ZETA_H
diff --git a/manifest.scm b/manifest.scm
new file mode 100644
index 0000000..a956edd
--- /dev/null
+++ b/manifest.scm
@@ -0,0 +1,6 @@
+(specifications->manifest
+ '("zup" ; Upload firmware over usb
+ "sdcc" ; Assembler and C compiler for the Z80 (and different other 8-bit CPUs)
+ "minipro" ; Write firmware directly to ROM
+ "python-intelhex" ; Convert output of compiler into raw binary data
+ ))
diff --git a/src/bootloader.c b/src/bootloader.c
new file mode 100644
index 0000000..0f67269
--- /dev/null
+++ b/src/bootloader.c
@@ -0,0 +1,310 @@
+#include <zeta.h>
+#include <tty.h>
+#include <hardware.h>
+#include <fifo.h>
+
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+
+#ifdef __GNUC__
+#define PACKED __attribute__((packed))
+#else
+#define PACKED
+#endif
+
+enum header_type {
+ CMD_PING,
+ CMD_INFO,
+ CMD_BOOT,
+ CMD_READ,
+ CMD_WRITE,
+ CMD_IO_READ,
+ CMD_IO_WRITE,
+ CMD_ECHO
+};
+
+struct header {
+ uint8_t type;
+ uint8_t bank;
+ uint16_t address;
+ uint16_t length;
+ uint16_t checksum;
+} PACKED;
+
+// static_assert(sizeof(struct header) == 8, "struct header is not PACKED");
+
+enum error {
+ ERR_TIMEOUT = -1
+};
+
+#define MAX_PACKET_SIZE 256
+#define TIMEOUT_MS 500
+#define MAX_ATTEMPTS 3
+#define MAX_TRANS_ATTEMPTS 5
+
+uint16_t
+crc16(const void *buf, size_t len);
+
+volatile struct fifo rx_fifo = {0, 0, {0}};
+
+enum ack {
+ ACK = 0x00,
+ NACK = 0xFF
+};
+
+void
+rx_isr(void) __critical __interrupt(0)
+{
+ fifo_push(&rx_fifo, sio_a_data);
+}
+
+static volatile uint32_t millis = 0;
+
+void
+ctc1_isr(void) __critical __interrupt(1)
+{
+ millis += 5;
+}
+
+uint32_t
+clock(void)
+{
+ volatile uint32_t ret;
+ DI;
+ ret = millis;
+ EI;
+ return ret;
+}
+
+void
+putbyte(unsigned char b)
+{
+ unsigned char ctrl = 0;
+
+ sio_a_data = b;
+
+ while (!(ctrl & 0x04)) {
+ sio_a_ctrl = 0;
+ ctrl = sio_a_ctrl;
+ }
+}
+
+static volatile int32_t errno = 0;
+
+uint8_t
+getbyte(void)
+{
+ uint8_t b;
+ uint32_t ms = clock();
+ errno = 0;
+ while (fifo_empty(&rx_fifo)) {
+ if (clock() - ms > TIMEOUT_MS) {
+ errno = ERR_TIMEOUT;
+ return 0;
+ }
+ }
+ DI;
+ b = fifo_pop(&rx_fifo);
+ EI;
+ return b;
+}
+
+void
+flush(void)
+{
+ DI;
+ fifo_clear(&rx_fifo);
+ EI;
+}
+
+
+// Hamming(7,4) encoding
+uint8_t
+encode(uint8_t x)
+{
+ uint8_t y = 0;
+ const uint8_t c[4] = {0x61, 0x52, 0x34, 0x78};
+
+ for (uint8_t i = 0; i < 4; ++i)
+ y ^= ((x >> i) & 1) ? c[i] : 0;
+
+ return y;
+}
+
+// Hamming(7,4) decoding
+uint8_t
+decode(uint8_t x)
+{
+ uint8_t p = 0;
+ const uint8_t r[7] = {6, 5, 3, 7, 1, 2, 4};
+
+ for (int i = 0; i < 7; ++i)
+ p ^= ((x >> i) & 1) ? r[i] : 0;
+
+ // Assume simple error, attempt correction
+ if (p) {
+ size_t i = 0;
+
+ for (i = 0; i < LENGTH(r); ++i) {
+ if (r[i] == x)
+ break;
+ }
+
+ x ^= (1 << i);
+ }
+
+ return x & 0x0F;
+}
+
+
+int
+read(void *buf, size_t count)
+{
+ uint8_t b;
+ uint8_t *p = buf;
+
+ for (int n = 0; n < count; ++n) {
+ b = decode(getbyte());
+ if (errno)
+ return errno;
+
+ b |= (decode(getbyte()) << 4);
+ if (errno)
+ return errno;
+
+ p[n] = b;
+ }
+
+ return 0;
+}
+
+int
+write(const void *buf, size_t count)
+{
+ const uint8_t *p = buf;
+
+ for (size_t i = 0; i < count; ++i) {
+ putbyte(encode(p[i] & 0x0F));
+ putbyte(encode((p[i] >> 4) & 0x0F));
+ }
+
+ return 0;
+}
+
+int
+read_header(struct header *header)
+{
+ int err;
+ uint8_t ack;
+ uint16_t checksum;
+
+ while (1) {
+ if ((err = read(header, sizeof(*header))))
+ return err;
+
+ checksum = header->checksum;
+ header->checksum = 0;
+
+ if (checksum == crc16(header, sizeof(*header))) {
+ header->checksum = checksum;
+ ack = ACK;
+ write(&ack, sizeof(ack));
+ return 0;
+ } else {
+ ack = NACK;
+ write(&ack, sizeof(ack));
+ }
+ }
+}
+
+int
+read_buf(size_t len, void *buf)
+{
+ int err;
+ uint8_t ack;
+ uint16_t checksum;
+
+ for (int i = 0; i < MAX_TRANS_ATTEMPTS; ++i) {
+ // TODO: reduce code?
+ if ((err = read(&checksum, sizeof(checksum)))
+ || (err = read(buf, len)))
+ break;
+
+ if (checksum == crc16(buf, len)) {
+ ack = ACK;
+ write(&ack, sizeof(ack));
+ return 0;
+ } else {
+ ack = NACK;
+ write(&ack, sizeof(ack));
+ }
+ }
+
+ return -1;
+}
+
+int
+write_buf(size_t len, const void *buf)
+{
+ int err;
+ uint8_t ack = NACK;
+ uint16_t checksum = crc16(buf, len);
+
+ for (int i = 0; i < MAX_TRANS_ATTEMPTS; ++i){
+ write(&checksum, sizeof(checksum));
+ write(buf, len);
+
+ // If TIMEOUT sending just give up
+ if ((err = read(&ack, sizeof(ack))))
+ return err;
+
+ if (ack == ACK)
+ return 0;
+ }
+
+ return -1;
+}
+
+// TODO: Restart after timeouts
+void
+bootloader(void)
+{
+ struct header header;
+ uint8_t buf[MAX_PACKET_SIZE];
+
+ const char *msg = "Bootloader ...\r\n";
+ addstr(msg);
+
+ while (1) {
+ if (read_header(&header)) {
+ flush();
+ continue;
+ }
+
+ switch (header.type) {
+ case CMD_BOOT:
+ ((void (*)(void))header.address)();
+ break;
+
+ case CMD_READ:
+ write_buf(header.length, (const void *)header.address);
+ break;
+
+ case CMD_WRITE:
+ if (!read_buf(header.length, buf))
+ memcpy((void *)header.address, buf, header.length);
+ break;
+
+ case CMD_ECHO:
+ if (!read_buf(header.length, buf))
+ write_buf(header.length, buf);
+ break;
+
+ default:
+ break;
+ }
+
+ flush();
+ }
+}
diff --git a/src/crc16.c b/src/crc16.c
new file mode 100644
index 0000000..6c80738
--- /dev/null
+++ b/src/crc16.c
@@ -0,0 +1,48 @@
+#include <zeta.h>
+
+static const u16 crc_table[256] = {
+ 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
+ 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
+ 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
+ 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
+ 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
+ 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
+ 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
+ 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
+ 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
+ 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
+ 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
+ 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
+ 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
+ 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
+ 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
+ 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
+ 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
+ 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
+ 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
+ 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
+ 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
+ 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
+ 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
+ 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
+ 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
+ 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
+ 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
+ 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
+ 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
+ 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
+ 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
+ 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
+};
+
+u16
+crc16(const void *buf, size_t len)
+{
+ const u8 *p = buf;
+
+ u16 crc = 0;
+ while (len--)
+ crc = crc_table[(crc >> 8) ^ (*p++)] ^ (crc << 8);
+
+ return crc;
+}
diff --git a/src/fifo.c b/src/fifo.c
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/src/fifo.c
diff --git a/src/font.c b/src/font.c
new file mode 100644
index 0000000..c6eb038
--- /dev/null
+++ b/src/font.c
@@ -0,0 +1,101 @@
+#include <stdint.h>
+
+const uint8_t font[97][8] = {
+ {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, /* SPACE */
+ {0x18, 0x18, 0x18, 0x18, 0x00, 0x00, 0x18, 0x00}, /* ! */
+ {0x66, 0x66, 0x66, 0x00, 0x00, 0x00, 0x00, 0x00}, /* " */
+ {0x66, 0x66, 0xFF, 0x66, 0xFF, 0x66, 0x66, 0x00}, /* # */
+ {0x18, 0x7C, 0x06, 0x3C, 0x60, 0x3E, 0x18, 0x00}, /* $ */
+ {0x46, 0x66, 0x30, 0x18, 0x0C, 0x66, 0x62, 0x00}, /* % */
+ {0x3C, 0x66, 0x3C, 0x1C, 0xE6, 0x66, 0xFC, 0x00}, /* & */
+ {0x60, 0x30, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00}, /* ' */
+ {0x30, 0x18, 0x0C, 0x0C, 0x0C, 0x18, 0x30, 0x00}, /* ( */
+ {0x0C, 0x18, 0x30, 0x30, 0x30, 0x18, 0x0C, 0x00}, /* ) */
+ {0x00, 0x66, 0x3C, 0xFF, 0x3C, 0x66, 0x00, 0x00}, /* * */
+ {0x00, 0x18, 0x18, 0x7E, 0x18, 0x18, 0x00, 0x00}, /* + */
+ {0x00, 0x00, 0x00, 0x00, 0x00, 0x18, 0x18, 0x0C}, /* , */
+ {0x00, 0x00, 0x00, 0x7E, 0x00, 0x00, 0x00, 0x00}, /* - */
+ {0x00, 0x00, 0x00, 0x00, 0x00, 0x18, 0x18, 0x00}, /* . */
+ {0x00, 0xC0, 0x60, 0x30, 0x18, 0x0C, 0x06, 0x00}, /* / */
+ {0x3C, 0x66, 0x76, 0x6E, 0x66, 0x66, 0x3C, 0x00}, /* 0 */
+ {0x18, 0x18, 0x1C, 0x18, 0x18, 0x18, 0x7E, 0x00}, /* 1 */
+ {0x3C, 0x66, 0x60, 0x30, 0x0C, 0x06, 0x7E, 0x00}, /* 2 */
+ {0x3C, 0x66, 0x60, 0x38, 0x60, 0x66, 0x3C, 0x00}, /* 3 */
+ {0x60, 0x70, 0x78, 0x66, 0xFE, 0x60, 0x60, 0x00}, /* 4 */
+ {0x7E, 0x06, 0x3E, 0x60, 0x60, 0x66, 0x3C, 0x00}, /* 5 */
+ {0x3C, 0x66, 0x06, 0x3E, 0x66, 0x66, 0x3C, 0x00}, /* 6 */
+ {0x7E, 0x66, 0x30, 0x18, 0x18, 0x18, 0x18, 0x00}, /* 7 */
+ {0x3C, 0x66, 0x66, 0x3C, 0x66, 0x66, 0x3C, 0x00}, /* 8 */
+ {0x3C, 0x66, 0x66, 0x7C, 0x60, 0x66, 0x3C, 0x00}, /* 9 */
+ {0x00, 0x00, 0x18, 0x00, 0x00, 0x18, 0x00, 0x00}, /* : */
+ {0x00, 0x00, 0x18, 0x00, 0x00, 0x18, 0x18, 0x0C}, /* / */
+ {0x70, 0x18, 0x0C, 0x06, 0x0C, 0x18, 0x70, 0x00}, /* < */
+ {0x00, 0x00, 0x7E, 0x00, 0x7E, 0x00, 0x00, 0x00}, /* = */
+ {0x0E, 0x18, 0x30, 0x60, 0x30, 0x18, 0x0E, 0x00}, /* > */
+ {0x3C, 0x66, 0x60, 0x30, 0x18, 0x00, 0x18, 0x00}, /* ? */
+ {0x3C, 0x66, 0x76, 0x76, 0x06, 0x46, 0x3C, 0x00}, /* @ */
+ {0x18, 0x3C, 0x66, 0x7E, 0x66, 0x66, 0x66, 0x00}, /* A */
+ {0x3E, 0x66, 0x66, 0x3E, 0x66, 0x66, 0x3E, 0x00}, /* B */
+ {0x3C, 0x66, 0x06, 0x06, 0x06, 0x66, 0x3C, 0x00}, /* C */
+ {0x1E, 0x36, 0x66, 0x66, 0x66, 0x36, 0x1E, 0x00}, /* D */
+ {0x7E, 0x06, 0x06, 0x1E, 0x06, 0x06, 0x7E, 0x00}, /* E */
+ {0x7E, 0x06, 0x06, 0x1E, 0x06, 0x06, 0x06, 0x00}, /* F */
+ {0x3C, 0x66, 0x06, 0x76, 0x66, 0x66, 0x3C, 0x00}, /* G */
+ {0x66, 0x66, 0x66, 0x7E, 0x66, 0x66, 0x66, 0x00}, /* H */
+ {0x3C, 0x18, 0x18, 0x18, 0x18, 0x18, 0x3C, 0x00}, /* I */
+ {0x78, 0x30, 0x30, 0x30, 0x30, 0x36, 0x1C, 0x00}, /* J */
+ {0x66, 0x36, 0x1E, 0x0E, 0x1E, 0x36, 0x66, 0x00}, /* K */
+ {0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x7E, 0x00}, /* L */
+ {0xC6, 0xEE, 0xFE, 0xD6, 0xC6, 0xC6, 0xC6, 0x00}, /* M */
+ {0x66, 0x6E, 0x7E, 0x7E, 0x76, 0x66, 0x66, 0x00}, /* N */
+ {0x3C, 0x66, 0x66, 0x66, 0x66, 0x66, 0x3C, 0x00}, /* O */
+ {0x3E, 0x66, 0x66, 0x3E, 0x06, 0x06, 0x06, 0x00}, /* P */
+ {0x3C, 0x66, 0x66, 0x66, 0x66, 0x3C, 0x70, 0x00}, /* Q */
+ {0x3E, 0x66, 0x66, 0x3E, 0x1E, 0x36, 0x66, 0x00}, /* R */
+ {0x3C, 0x66, 0x06, 0x3C, 0x60, 0x66, 0x3C, 0x00}, /* S */
+ {0x7E, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x00}, /* T */
+ {0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x3C, 0x00}, /* U */
+ {0x66, 0x66, 0x66, 0x66, 0x66, 0x3C, 0x18, 0x00}, /* V */
+ {0xC6, 0xC6, 0xC6, 0xD6, 0xFE, 0xEE, 0xC6, 0x00}, /* W */
+ {0x66, 0x66, 0x3C, 0x18, 0x3C, 0x66, 0x66, 0x00}, /* X */
+ {0x66, 0x66, 0x66, 0x3C, 0x18, 0x18, 0x18, 0x00}, /* Y */
+ {0x7E, 0x60, 0x30, 0x18, 0x0C, 0x06, 0x7E, 0x00}, /* Z */
+ {0x3C, 0x0C, 0x0C, 0x0C, 0x0C, 0x0C, 0x3C, 0x00}, /* [ */
+ {0xC0, 0x60, 0x30, 0x18, 0x0C, 0x06, 0x02, 0x00}, /* \ */
+ {0x3C, 0x30, 0x30, 0x30, 0x30, 0x30, 0x3C, 0x00}, /* ] */
+ {0x10, 0x38, 0x6C, 0xC6, 0x00, 0x00, 0x00, 0x00}, /* ^ */
+ {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF}, /* _ */
+ {0x30, 0x30, 0x18, 0x00, 0x00, 0x00, 0x00, 0x00}, /* ` */
+ {0x00, 0x00, 0x3C, 0x60, 0x7C, 0x66, 0x7C, 0x00}, /* a */
+ {0x00, 0x06, 0x06, 0x3E, 0x66, 0x66, 0x3E, 0x00}, /* b */
+ {0x00, 0x00, 0x3C, 0x06, 0x06, 0x06, 0x3C, 0x00}, /* c */
+ {0x00, 0x60, 0x60, 0x7C, 0x66, 0x66, 0x7C, 0x00}, /* d */
+ {0x00, 0x00, 0x3C, 0x66, 0x7E, 0x06, 0x3C, 0x00}, /* e */
+ {0x00, 0x70, 0x18, 0x7C, 0x18, 0x18, 0x18, 0x00}, /* f */
+ {0x00, 0x00, 0x7C, 0x66, 0x66, 0x7C, 0x60, 0x3E}, /* g */
+ {0x00, 0x06, 0x06, 0x3E, 0x66, 0x66, 0x66, 0x00}, /* h */
+ {0x00, 0x18, 0x00, 0x1C, 0x18, 0x18, 0x3C, 0x00}, /* i */
+ {0x00, 0x60, 0x00, 0x60, 0x60, 0x60, 0x60, 0x3C}, /* j */
+ {0x00, 0x06, 0x06, 0x36, 0x1E, 0x36, 0x66, 0x00}, /* k */
+ {0x00, 0x1C, 0x18, 0x18, 0x18, 0x18, 0x3C, 0x00}, /* l */
+ {0x00, 0x00, 0x66, 0xFE, 0xFE, 0xD6, 0xC6, 0x00}, /* m */
+ {0x00, 0x00, 0x3E, 0x66, 0x66, 0x66, 0x66, 0x00}, /* n */
+ {0x00, 0x00, 0x3C, 0x66, 0x66, 0x66, 0x3C, 0x00}, /* o */
+ {0x00, 0x00, 0x3E, 0x66, 0x66, 0x3E, 0x06, 0x06}, /* p */
+ {0x00, 0x00, 0x7C, 0x66, 0x66, 0x7C, 0x60, 0x60}, /* q */
+ {0x00, 0x00, 0x3E, 0x66, 0x06, 0x06, 0x06, 0x00}, /* r */
+ {0x00, 0x00, 0x7C, 0x06, 0x3C, 0x60, 0x3E, 0x00}, /* s */
+ {0x00, 0x18, 0x7E, 0x18, 0x18, 0x18, 0x70, 0x00}, /* t */
+ {0x00, 0x00, 0x66, 0x66, 0x66, 0x66, 0x7C, 0x00}, /* u */
+ {0x00, 0x00, 0x66, 0x66, 0x66, 0x3C, 0x18, 0x00}, /* v */
+ {0x00, 0x00, 0xC6, 0xD6, 0xFE, 0x7C, 0x6C, 0x00}, /* w */
+ {0x00, 0x00, 0x66, 0x3C, 0x18, 0x3C, 0x66, 0x00}, /* x */
+ {0x00, 0x00, 0x66, 0x66, 0x66, 0x7C, 0x30, 0x1E}, /* y */
+ {0x00, 0x00, 0x7E, 0x30, 0x18, 0x0C, 0x7E, 0x00}, /* z */
+ {0x1C, 0x30, 0x30, 0xE0, 0x30, 0x30, 0x1C, 0x00}, /* { */
+ {0x18, 0x18, 0x18, 0x00, 0x18, 0x18, 0x18, 0x00}, /* | */
+ {0xE0, 0x30, 0x30, 0x1C, 0x30, 0x30, 0xE0, 0x00}, /* } */
+ {0x76, 0xDC, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, /* ~ */
+ {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}, /* DEL */
+ {0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF} /* CURSOR */
+};
diff --git a/src/i2c.c b/src/i2c.c
new file mode 100644
index 0000000..cca68c6
--- /dev/null
+++ b/src/i2c.c
@@ -0,0 +1,103 @@
+#include <i2c.h>
+#include <hardware.h>
+
+#define SDA (1 << 0)
+#define SCL (1 << 1)
+
+void
+_delay_ms(uint8_t ms);
+
+void
+i2c_start_condition(void)
+{
+ port_a_data &= ~SDA;
+ _delay_ms(1);
+ port_a_data &= ~SCL;
+ _delay_ms(1);
+}
+
+void
+i2c_restart_condition(void)
+{
+ port_a_data |= SDA;
+ _delay_ms(1);
+ port_a_data |= SCL;
+ _delay_ms(1);
+ i2c_start_condition();
+}
+
+void
+i2c_stop_condition(void)
+{
+ port_a_data |= SCL;
+ _delay_ms(1);
+ port_a_data |= SDA;
+ _delay_ms(1);
+}
+
+void
+i2c_send(uint8_t b)
+{
+ uint8_t i;
+
+ for (i = 0; i < 8; ++i) {
+ if (b & 1)
+ port_a_data |= SDA;
+ else
+ port_a_data &= ~SDA;
+
+ port_a_data |= SCL;
+ _delay_ms(1);
+ port_a_data &= ~SCL;
+ _delay_ms(1);
+
+ b >>= 1;
+ }
+
+ port_a_ctrl = PIO_MODE_3;
+ port_a_ctrl = 0x7D;
+
+ // Read ack
+ port_a_data |= SCL;
+ _delay_ms(1);
+ port_a_data &= ~SCL;
+ _delay_ms(1);
+
+ port_a_ctrl = PIO_MODE_3;
+ port_a_ctrl = 0x7C;
+}
+
+uint8_t
+i2c_recv(uint8_t ack)
+{
+ uint8_t i;
+ uint8_t b = 0;
+
+ port_a_ctrl = PIO_MODE_3;
+ port_a_ctrl = 0x7D;
+
+ for (i = 0; i < 8; ++i) {
+ port_a_data |= SCL;
+ _delay_ms(1);
+ if (port_a_data & 1)
+ b |= 1;
+
+ port_a_data &= ~SCL;
+ _delay_ms(1);
+ b <<= 1;
+ }
+
+ port_a_ctrl = PIO_MODE_3;
+ port_a_ctrl = 0x7C;
+
+ if (ack)
+ port_a_data |= SDA;
+ else
+ port_a_data &= ~SDA;
+
+ port_a_data |= SCL;
+ _delay_ms(1);
+ port_a_data &= ~SCL;
+ _delay_ms(1);
+ return b;
+}
diff --git a/src/input.c b/src/input.c
new file mode 100644
index 0000000..db306ea
--- /dev/null
+++ b/src/input.c
@@ -0,0 +1,59 @@
+#include <hardware.h>
+#include <tty.h>
+#include <stdint.h>
+#include <input.h>
+
+enum encoder_state {
+ START,
+ CW_START,
+ CW_NEXT,
+ CW_FINAL,
+ CCW_START,
+ CCW_NEXT,
+ CCW_FINAL,
+ CW = 0x10,
+ CCW = 0x20
+};
+
+/* State machine to keep track of encoder */
+static const uint8_t encoder_table[7][4] = {
+ /* 00 01 10 11*/
+ [START] = { START, CCW_START, CW_START, START },
+ [CCW_START] = { CCW_NEXT, CCW_START, START, START },
+ [CCW_NEXT] = { CCW_NEXT, CCW_START, CCW_FINAL, START },
+ [CCW_FINAL] = { CCW_NEXT, START, CCW_FINAL, START | CCW },
+ [CW_START] = { CW_NEXT, START, CW_START, START },
+ [CW_NEXT] = { CW_NEXT, CW_FINAL, CW_START, START },
+ [CW_FINAL] = { CW_NEXT, CW_FINAL, START, START | CW }
+};
+
+struct fifo input_fifo = {0, 0, {0}};
+
+void
+input_event(void) __critical __interrupt(4)
+{
+ if ((port_b_data & 0x03) != 0x03) {
+ // Encoder
+ uint8_t state = START;
+ uint8_t encoder;
+ uint8_t next_state;
+
+ do {
+ encoder = port_b_data & 0x03;
+ next_state = encoder_table[state][encoder];
+ state = next_state & 0x0F;
+ } while (state != START);
+
+ if (next_state == CW || next_state == CCW)
+ fifo_push(&input_fifo, next_state);
+ } else if (port_b_data & 0x7C) {
+ // Key pressed
+ for (int i = 0; i < 5; i++) {
+ uint8_t bit = 1 << (i + 2);
+ uint8_t state = !(port_b_data & bit);
+
+ if (state)
+ fifo_push(&input_fifo, i);
+ }
+ }
+}
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..fe3da0e
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,185 @@
+#include <tft.h>
+#include <tty.h>
+#include <i2c.h>
+#include <zeta.h>
+#include <input.h>
+
+void
+uart_putchar(char c);
+
+static inline void
+enable_input_fifo(void)
+{
+}
+
+static inline void
+disable_input_fifo(void)
+{
+}
+
+static inline void
+init_pio(void)
+{
+ // Control mode - i.e. no parallel port communication
+ port_b_ctrl = PIO_MODE_3;
+ // A, B and five keys as inputs
+ port_b_ctrl = 0x7F;
+ // Load interrupt vector
+ // port_b_ctrl = ISR_ADDRESS(port_b_isr_ptr);
+ // Interrupt word - interrupt if any pin goes low, mask follows
+ // port_b_ctrl = PIO_INT_CTRL(PIO_INT_EN | PIO_OR | PIO_LOW | PIO_MASK);
+ // Mask - 0 means to check line
+ // port_b_ctrl = 0x80;
+
+ /* port_a_ctrl = PIO_MODE_3; */
+
+ /* port_a_ctrl = 0x7C; */
+
+ /* // Load interrupt vector */
+ /* port_a_ctrl = ISR_ADDRESS(port_a_isr_ptr); */
+
+ /* port_a_ctrl = PIO_INT_CTRL(PIO_INT_EN | PIO_OR | PIO_HIGH | PIO_MASK); */
+ /* port_a_ctrl = 0x83; */
+
+ /* // SDA and SCL high */
+ /* port_a_data = 0x03; */
+}
+
+static inline void
+init_ctc(void)
+{
+ /* 200Hz clock */
+ ctc_channel_1 = CTC_CTRL(CTC_INT_BIT | CTC_PRESCALER_BIT
+ | CTC_TIME_CONST_BIT | CTC_RST_BIT);
+ ctc_channel_1 = 0;
+
+ /* 200Hz clock */
+ ctc_channel_2 = CTC_CTRL(CTC_INT_BIT | CTC_PRESCALER_BIT
+ | CTC_TIME_CONST_BIT | CTC_RST_BIT);
+ ctc_channel_2 = 0;
+
+ /* ctc_channel_3 = (CPU_FREQ / 256 / 144); */
+
+ ctc_channel_3 = CTC_CTRL(CTC_INT_BIT | CTC_PRESCALER_BIT
+ | CTC_TIME_CONST_BIT | CTC_RST_BIT);
+ ctc_channel_3 = 0; // 256
+
+ // Interrupt table for CTC
+ // Final address is (Ireg << 8) | ctc_isr_ptr | {00/01/10/11} | 0
+ ctc_channel_0 = ISR_ADDRESS(ctc0_isr_ptr);
+}
+
+static inline void
+init_sio(void)
+{
+ static const u8 sio_a_cfg[] = {
+ 0b00011000, // Reset channel
+ 4 , // wr4
+ 0b01000100, // X16 clock (115200), one stop bit, no parity
+ 1 , // wr1
+ SIO_RX_INT_MD0 | SIO_RX_INT_MD1, // interrupt on every Rx, no wait function
+ 3 , // wr3
+ 0b11000001, // enable Rx - 8 bit char
+ 5 , // wr5
+ 0b01101000 // enable Tx - 8 bit char
+ };
+
+ static const u8 sio_b_cfg[] = {
+ 0b00011000, // Reset channel
+ 2 , // load interrupt vector
+ ISR_ADDRESS(rx_isr_ptr) // int_table_rx
+ };
+
+ for (u8 i = 0; i < LENGTH(sio_a_cfg); ++i)
+ sio_a_ctrl = sio_a_cfg[i];
+
+ for (u8 i = 0; i < LENGTH(sio_b_cfg); ++i)
+ sio_b_ctrl = sio_b_cfg[i];
+}
+
+// copy code to ram, so function pointer is modifyable
+
+static uint8_t tick = 0;
+
+void
+timer(void) __critical __interrupt(5)
+{
+ static int prescale = 0;
+
+ if (++prescale == 150) {
+ prescale = 0;
+ tick = 1;
+ }
+}
+
+/* i2c_start_condition(); */
+/* i2c_send(0xA0); */
+/* i2c_send(0x00); */
+/* i2c_send(0x00); */
+/* i2c_restart_condition(); */
+/* i2c_send(0xA1); */
+/* b = i2c_recv(NACK); */
+/* i2c_stop_condition(); */
+
+void
+main(void)
+{
+ tft_init();
+
+ init_ctc();
+ init_pio();
+ init_sio();
+
+ // Interrupt mode 2
+ IM(2);
+ // Enable interrupts
+ EI;
+
+ // Boot menu
+ addstr("1) Programming mode\r\n");
+ addstr("2) Normal boot (default)\r\n");
+ addstr("3) Boot address 0xC000\r\n");
+
+ for (int i = 5; i > 0; --i) {
+ addch('\r');
+ addch(i + '0');
+
+ while (!tick) {
+ u8 keys = poll_keys();
+
+ if (!(keys & KEY2)) {
+ addch('\r');
+ bootloader();
+ }
+
+ if (!(keys & KEY3)) {
+ goto boot;
+ }
+
+ if (!(keys & KEY4)) {
+ // Definitely safe looking C code ...
+ void (*ptr)(void) = (void (*)(void))0xC000;
+ ptr();
+ }
+ }
+
+ DI;
+ tick = 0;
+ EI;
+ }
+
+ addch('\r');
+
+boot:
+ addstr("Starting system ...\r\n");
+ // Load interrupt vector
+ port_b_ctrl = ISR_ADDRESS(port_b_isr_ptr);
+ // Interrupt word - interrupt if any pin goes low, mask follows
+ port_b_ctrl = PIO_INT_CTRL(PIO_INT_EN | PIO_OR | PIO_LOW | PIO_MASK);
+ // Mask - 0 means to check line
+ port_b_ctrl = 0x80;
+ _menu();
+
+ while (1)
+ ;
+}
diff --git a/src/menu.c b/src/menu.c
new file mode 100644
index 0000000..51f7c31
--- /dev/null
+++ b/src/menu.c
@@ -0,0 +1,269 @@
+#include <zeta.h>
+#include <hardware.h>
+#include <tty.h>
+#include <input.h>
+#include <stdio.h>
+#include <string.h>
+
+struct time {
+ uint8_t second;
+ uint8_t minute;
+ uint8_t hour;
+ uint8_t wkday;
+ uint8_t date;
+ uint8_t month;
+ uint8_t year;
+};
+
+struct value {
+ uint8_t roll;
+ int val;
+ int min, max;
+};
+
+void
+value_inc(struct value *v, int d)
+{
+ v->val += d;
+
+ if (v->roll) {
+ if (v->val > v->max)
+ v->val = v->min;
+ else if(v->val < v->min)
+ v->val = v->max - 1;
+ } else {
+ v->val = clamp(v->val, v->min, v->max);
+ }
+}
+
+enum item_type {
+ VOID,
+ BUTTON,
+ VALUE,
+ LABEL
+};
+
+void
+draw_time(void)
+{
+ char buf[32];
+ struct time time;
+ memset(&time, 0, sizeof(time));
+ // rtc_get_bcd_time(&time);
+ sprintf(buf, "20%hhd%hhd-%hhd%hhd-%hhd%hhd %hhd%hhd:%hhd%hhd:%hhd%hhd",
+ time.year >> 4, time.year & 0xF,
+ time.month >> 4, time.month & 0xF,
+ time.date >> 4, time.date & 0xF,
+ time.hour >> 4, time.hour & 0xF,
+ time.minute >> 4, time.minute & 0xF,
+ time.second >> 4, time.second & 0xF);
+ mvaddstr(5, 1, buf);
+}
+
+void
+draw_battery(void)
+{
+ uint16_t soc = 100; // bat_state_of_charge();
+ char buf[16];
+ sprintf(buf, "%u%%", soc);
+ mvaddstr(7, 1, buf);
+}
+
+void
+set_time(void);
+
+struct item {
+ uint8_t type;
+ const char *text;
+ union {
+ void (*action)(void);
+ struct value value;
+ } v;
+};
+
+struct menu_entry {
+ const char *text;
+ struct item items[8];
+};
+
+struct menu_entry menu[] = {
+ {
+ .text = "TIME ",
+ .items = {
+ {.type = LABEL, .v = {.action = draw_time}},
+ {.type = LABEL, .v = {.action = draw_battery}},
+ {.type = VOID},
+ {.type = VOID},
+ {.type = VOID},
+ {.type = VOID},
+ {.type = VOID},
+ {.type = VOID}
+ }
+ },
+ {
+ .text = "CONF ",
+ .items = {
+ {.type = VALUE, .text = "SEC", .v = {.value = {1, 0, 0, 59}}},
+ {.type = VALUE, .text = "MIN", .v = {.value = {1, 0, 0, 59}}},
+ {.type = VALUE, .text = "HOUR", .v = {.value = {1, 0, 0, 23}}},
+ {.type = VALUE, .text = "WKDAY", .v = {.value = {1, 0, 1, 7}}},
+ {.type = VALUE, .text = "DATE", .v = {.value = {1, 1, 1, 31}}},
+ {.type = VALUE, .text = "MONTH", .v = {.value = {1, 1, 1, 12}}},
+ {.type = VALUE, .text = "YEAR", .v = {.value = {1, 0, 0, 3000}}},
+ {.type = BUTTON, .text = "LOAD", .v = {.action = set_time}}
+ }
+ }
+};
+
+void
+set_time(void)
+{
+ struct time time;
+ struct item *items = menu[1].items;
+
+ time.second = items[0].v.value.val;
+ time.minute = items[1].v.value.val;
+ time.hour = items[2].v.value.val;
+ time.wkday = items[3].v.value.val;
+ time.date = items[4].v.value.val;
+ time.month = items[5].v.value.val;
+ time.year = items[6].v.value.val;
+
+ // rtc_set_time(&time);
+}
+
+enum direction {
+ VERTICAL,
+ HORIZONTAL
+};
+
+static uint8_t dir = HORIZONTAL;
+static int menu_index = 0;
+static int sub_menu_index = -1;
+static int edit = 0;
+
+#define BUILD_VERSION "20241117"
+
+void
+draw_menu(void)
+{
+ const char *build_version = BUILD_VERSION;
+ const int padding = (TTY_WIDTH - 8 * LENGTH(menu)) / 2;
+
+ mvaddstr(1, 0, " ************* THE SOUTHERN STAR MK II ************* ");
+ mvaddch(3, 1, dir == HORIZONTAL ? '>' : '^');
+
+ for (int i = 0; i < LENGTH(menu); ++i) {
+ if (i == menu_index) {
+ swap_colors();
+ mvaddstr(3, padding + i * 8, menu[i].text);
+ swap_colors();
+ } else {
+ mvaddstr(3, padding + i * 8, menu[i].text);
+ }
+ }
+
+ const struct menu_entry *entry = &menu[menu_index];
+
+ for (int i = 0; i < LENGTH(entry->items); ++i) {
+ mvaddstr(5 + 2 * i, 1, " ");
+
+ if (entry->items[i].type == VOID)
+ continue;
+
+ if (i == sub_menu_index && menu_index != 0) {
+ swap_colors();
+ mvaddstr(5 + 2 * i, 1, entry->items[i].text);
+ swap_colors();
+ } else {
+ mvaddstr(5 + 2 * i, 1, entry->items[i].text);
+ }
+
+ if (entry->items[i].type == VALUE) {
+ char buf[16];
+ sprintf(buf, "%8d", entry->items[i].v.value.val);
+ mvaddstr(5 + 2 * i, 6, buf);
+ }
+
+ if (entry->items[i].type == LABEL) {
+ entry->items[i].v.action();
+ }
+ }
+
+ mvaddstr(TTY_HEIGHT - 2, TTY_WIDTH - strlen(build_version) - 1, build_version);
+}
+
+void
+dir_callback(void)
+{
+ if (sub_menu_index >= 0) {
+ struct item *item = &menu[menu_index].items[sub_menu_index];
+
+ switch (item->type) {
+ case VALUE:
+ edit = !edit;
+ break;
+
+ case BUTTON:
+ if (item->v.action)
+ item->v.action();
+ break;
+ }
+ } else {
+ dir = (dir + 1) & 1;
+ draw_menu();
+ }
+}
+
+#define CW 0x10
+#define CCW 0x20
+
+typedef void (*callback)(void);
+volatile callback callbacks[5] = {NULL, NULL, NULL, NULL, NULL};
+
+void
+_menu(void)
+{
+ callbacks[0] = dir_callback;
+ clear_screen();
+ setcur(0, 0);
+ draw_menu();
+
+ while (1) {
+ DI;
+ while (!fifo_empty(&input_fifo)) {
+ u8 event = fifo_pop(&input_fifo);
+ if (event == CW) {
+ if (dir == HORIZONTAL) {
+ if (++menu_index >= LENGTH(menu))
+ menu_index = 0;
+ } else {
+ if (edit) {
+ value_inc(&menu[menu_index].items[sub_menu_index].v.value, 1);
+ } else {
+ if (++sub_menu_index >= LENGTH(menu[0].items))
+ sub_menu_index = 0;
+ }
+ }
+ draw_menu();
+ } else if (event == CCW) {
+ if (dir == HORIZONTAL) {
+ if (--menu_index < 0)
+ menu_index = LENGTH(menu) - 1;
+ } else {
+ if (edit) {
+ value_inc(&menu[menu_index].items[sub_menu_index].v.value, -1);
+ } else {
+ if (--sub_menu_index < -1)
+ sub_menu_index = LENGTH(menu[0].items) - 1;
+ }
+ }
+ draw_menu();
+ } else {
+ if (callbacks[event])
+ callbacks[event]();
+ }
+ }
+ EI;
+ }
+}
diff --git a/src/tft.c b/src/tft.c
new file mode 100644
index 0000000..d0c7d8f
--- /dev/null
+++ b/src/tft.c
@@ -0,0 +1,138 @@
+#include <tft.h>
+#include <hardware.h>
+#include <zeta.h>
+
+void
+_delay_ms(uint8_t ms);
+
+/*
+ * Driver for the ILI9341 TFT Chip
+ */
+
+static inline void
+tft_soft_reset(void)
+{
+ tft_ctrl = SWRESET;
+}
+
+static inline void
+tft_enable_ext_cmd(void)
+{
+ tft_ctrl = SETEXTC;
+ tft_data = 0xFF;
+ tft_data = 0x83;
+ tft_data = 0x57;
+}
+
+static inline void
+tft_memory_access_ctrl(uint8_t bits)
+{
+ tft_ctrl = MADCTL;
+ tft_data = bits;
+}
+
+static inline void
+tft_sleep_out(void) {
+ tft_ctrl = SLPOUT;
+}
+
+static inline void
+tft_display_on(void)
+{
+ tft_ctrl = DISPON;
+}
+
+static inline void
+tft_pixel_format(uint8_t dbi, uint8_t dpi)
+{
+ tft_ctrl = COLMOD;
+ tft_data = (dpi << 4) | dbi;
+}
+
+static inline void
+tft_set_rgb_interface(void)
+{
+ tft_ctrl = SETRGB;
+ tft_data = 0x00;
+ tft_data = 0x00;
+ tft_data = 0x06;
+ tft_data = 0x06;
+}
+
+static inline void
+tft_set_col_addr(uint16_t start, uint16_t end)
+{
+ tft_ctrl = CASET;
+ tft_data = start >> 8;
+ tft_data = start & 0xFF;
+ tft_data = end >> 8;
+ tft_data = end & 0xFF;
+}
+
+static inline void
+tft_set_page_addr(uint16_t start, uint16_t end)
+{
+ tft_ctrl = PASET;
+ tft_data = start >> 8;
+ tft_data = start & 0xFF;
+ tft_data = end >> 8;
+ tft_data = end & 0xFF;
+}
+
+void
+tft_set_area(unsigned int x, unsigned int y, unsigned int w, unsigned int h)
+{
+ tft_set_col_addr(x, x + w - 1);
+ tft_set_page_addr(y, y + h - 1);
+}
+
+enum memory_access {
+ // MY MX MV ML | BGR SS X X
+ MV = 0x20, // 1: landscape 0 <= x < 480; 0 <= y < 320
+ MX = 0x40, // MV = 0: Invert X; MV = 1: Invert Y
+ MY = 0x80, // MV = 0: Invert Y; MV = 1: Invert X
+ ML = 0x10
+};
+
+void
+clear_screen(void)
+{
+ DI;
+ tft_set_col_addr(0, TFT_WIDTH - 1);
+ tft_set_page_addr(0, TFT_HEIGHT - 1);
+
+ tft_ctrl = RAMWR;
+ for (u16 i = 0; i < TFT_HEIGHT; ++i) {
+ for (u16 j = 0; j < TFT_WIDTH; ++j) {
+ tft_data = 0x00;
+ tft_data = 0x00;
+ tft_data = 0x00;
+ }
+ }
+ EI;
+}
+
+void
+tft_init(void)
+{
+ _delay_ms(200);
+
+ tft_soft_reset();
+ tft_enable_ext_cmd();
+
+ _delay_ms(250);
+
+ tft_set_rgb_interface();
+
+ tft_pixel_format(BIT18, BIT18);
+
+ tft_memory_access_ctrl(MV | 0x0C);
+ tft_sleep_out();
+
+ _delay_ms(150);
+
+ tft_display_on();
+
+ _delay_ms(50);
+ clear_screen();
+}
diff --git a/src/tty.c b/src/tty.c
new file mode 100644
index 0000000..f9413b4
--- /dev/null
+++ b/src/tty.c
@@ -0,0 +1,164 @@
+#include <tft.h>
+#include <zeta.h>
+#include <tty.h>
+
+struct color {
+ uint8_t r, g, b;
+};
+
+static unsigned int row = 0;
+static unsigned int col = 0;
+
+// Index of first row inside buf
+static volatile uint8_t head = 0;
+
+// TTY's current contents
+static volatile uint8_t buf[TTY_HEIGHT][TTY_WIDTH];
+
+static volatile struct color bg_color = {0x00, 0x00, 0x00};
+static volatile struct color fg_color = {0xFF, 0xFB, 0x00};
+
+extern const uint8_t font[97][8];
+
+
+static uint8_t cursor = 0;
+static uint8_t timer = 0;
+
+void
+blink_cursor(void) __critical __interrupt(3)
+{
+ if (++timer >= 75) {
+ uint8_t i;
+
+ tft_set_area(8 * col, 8 * row, 8, 8);
+ tft_ram_wr();
+
+ if ((cursor ^= 1)) {
+ for (i = 0; i < 64; ++i)
+ tft_pixel(fg_color.r, fg_color.g, fg_color.b);
+ } else {
+ for (i = 0; i < 64; ++i)
+ tft_pixel(bg_color.r, bg_color.g, bg_color.b);
+ }
+ timer = 0;
+ }
+}
+
+static void
+draw(u8 c)
+{
+ u8 i, j;
+ const u8 *chr;
+
+ if (c < ' ')
+ return;
+
+ chr = font[c - ' '];
+
+ tft_ram_wr();
+
+ for (i = 0; i < 8; ++i) {
+ u8 row = chr[i];
+ for (j = 0; j < 8; ++j) {
+ if (row & 1)
+ tft_pixel(fg_color.r, fg_color.g, fg_color.b);
+ else
+ tft_pixel(bg_color.r, bg_color.g, bg_color.b);
+ row >>= 1;
+ }
+ }
+}
+
+static void
+scroll(void)
+{
+ uint16_t i, j;
+ head = (head + 1) % TTY_HEIGHT;
+
+ for (i = head; i < TTY_HEIGHT; ++i) {
+ for (j = 0; j < TTY_WIDTH; ++j) {
+ tft_set_area(8 * j, 8 * (i - head), 8, 8);
+ draw(buf[i][j]);
+ }
+ }
+
+ for (i = 0; i < head - 1; ++i) {
+ for (j = 0; j < TTY_WIDTH; ++j) {
+ tft_set_area(8 * j, 8 * (TTY_HEIGHT - head + i), 8, 8);
+ draw(buf[i][j]);
+ }
+ }
+
+ for (j = 0; j < TTY_WIDTH; ++j) {
+ tft_set_area(8 * j, 8 * (TTY_HEIGHT - 1), 8, 8);
+ draw(' ');
+ }
+}
+
+static void
+newline(void)
+{
+ if (++row >= TTY_HEIGHT) {
+ row = TTY_HEIGHT - 1;
+ scroll();
+ }
+}
+
+static void
+advance(void)
+{
+ if (++col >= TTY_WIDTH) {
+ newline();
+ col = 0;
+ }
+}
+
+void
+addch(char c)
+{
+ switch (c) {
+ case '\b':
+ if (col != 0)
+ --col;
+ return;
+
+ case '\r':
+ col = 0;
+ return;
+
+ case '\n':
+ newline();
+ return;
+ }
+
+ tft_set_area(8 * col, 8 * row, 8, 8);
+
+ draw(c);
+
+ buf[(head + row) % TTY_HEIGHT][col] = c;
+ advance();
+}
+
+void
+setcur(unsigned int ncol, unsigned int nrow)
+{
+ col = ncol;
+ row = nrow;
+}
+
+void
+swap_colors(void)
+{
+ struct color tmp = {fg_color.r, fg_color.g, fg_color.b};
+ fg_color = bg_color;
+ bg_color = tmp;
+}
+
+void
+addstr(const char *str)
+{
+ while (*str) {
+ addch(*str);
+ ++str;
+ }
+}