Add bootloader

8 files changed, 597 insertions, 45 deletions

diff --git a/Makefile b/Makefile
index b1b2c0d..ea09b19 100644
--- a/Makefile
+++ b/Makefile
@@ -15,14 +15,16 @@ SRC=font.c\
 	tty.c\
 	menu.c
 
-OBJ=$(ASM:%.asm=build/%.rel)\
-	$(SRC:%.c=build/%.rel)
+INCLUDE=include
+BUILD=build
 
-IHX=build/$(PROJECT).ihx
-TARGET=build/$(PROJECT).hex
-BOOTLOADER=build/boot/bootloader.hex
+OBJ=$(ASM:%.asm=$(BUILD)/%.rel)\
+	$(SRC:%.c=$(BUILD)/%.rel)
+
+IHX=$(BUILD)/$(PROJECT).ihx
+TARGET=$(BUILD)/$(PROJECT).hex
+BOOTLOADER=$(BUILD)/boot/bootloader.hex
 
-INCLUDE=include
 CFLAGS=-mz80 -I$(INCLUDE) --Werror
 LDFLAGS=-mz80 --no-std-crt0\
 		--code-loc 0x0100\
@@ -34,17 +36,17 @@ ROM_CHIP=AT28C256
 
 all : $(TARGET)
 
-$(OBJ): | build
+$(OBJ): | $(BUILD)
 
-build:
-	@mkdir -p build
+$(BUILD):
+	@mkdir -p $(BUILD)
 
-build/%.rel : asm/%.asm
+$(BUILD)/%.rel : asm/%.asm
 	@echo '  (AS)' $<
-	@$(CPP) -P -I$(INCLUDE) -DASSEMBLY $< > build/$(notdir $<)
-	@$(AS) -g -o $@ build/$(notdir $<)
+	@$(CPP) -P -I$(INCLUDE) -DASSEMBLY $< > $(BUILD)/$(notdir $<)
+	@$(AS) -g -o $@ $(BUILD)/$(notdir $<)
 
-build/%.rel : src/%.c
+$(BUILD)/%.rel : src/%.c
 	@echo '  (CC)' $<
 	@$(CC) $(CFLAGS) -c -o $@ $<
 
@@ -54,15 +56,16 @@ $(IHX) : $(OBJ)
 
 $(TARGET) : $(IHX) $(BOOTLOADER)
 	@hex2bin.py -l 32768 $< $@
-	@dd if=$(BOOTLOADER) of=$@ obs=1024 seek=28 conv=notrunc
+	@dd if=$(BOOTLOADER) of=$@ obs=1024 seek=28 conv=notrunc 2>/dev/null
 
+.PHONY : $(BOOTLOADER)
 $(BOOTLOADER) :
-	make -C boot
+	@make -C boot
 
-.PHONE : flash
+.PHONY : flash
 flash :
 	@minipro -y -sp $(ROM_CHIP) -w $(TARGET)
 
 .PHONY : clean
 clean :
-	@find build -type f -delete
+	@find $(BUILD) -type f -delete
diff --git a/asm/crt0.asm b/asm/crt0.asm
index 523c39e..fd03997 100644
--- a/asm/crt0.asm
+++ b/asm/crt0.asm
@@ -6,22 +6,22 @@
 	.area	_HEADER (ABS)
     .org    0x0000
 start:
+    di
     xor     a
     ld      i, a
     ld      sp, #0x0000
-    di
     ;; Init PIO and check for KEY2
     ld      a, #PIO_MODE_3
     out     (PORT_B_CTRL), a
     ld      a, #0x7F
     out     (PORT_B_CTRL), a
     in      a, (PORT_B_DATA)
-    and     #0x02               ; is KEY2 pressed? If so, start booloader
+    and     #KEY2               ; is KEY2 pressed? If so, start booloader
     jr      NZ, main
     ;; Load payload (bootloader)
-    ld      HL, #0x7000
-    ld      DE, #0x8000
-    ld      BC, #0x1000
+    ld      hl, #0x7000         ; src
+    ld      de, #0x8000         ; dest
+    ld      bc, #0x1000         ; size
     ldir
     ;; Start bootloader
     jp      0x8000
diff --git a/boot/Makefile b/boot/Makefile
new file mode 100644
index 0000000..2fff22d
--- /dev/null
+++ b/boot/Makefile
@@ -0,0 +1,50 @@
+AS=sdasz80
+CC=sdcc
+CPP=sdcpp
+
+ASM=crt0.asm
+SRC=crc16.c\
+	bootloader.c
+
+INCLUDE=../include
+BUILD=../build/boot
+
+OBJ=$(ASM:%.asm=$(BUILD)/%.rel)\
+	$(SRC:%.c=$(BUILD)/%.rel)
+
+IHX=$(BUILD)/bootloader.ihx
+TARGET=$(BUILD)/bootloader.hex
+
+CFLAGS=-mz80 -I$(INCLUDE) --Werror
+LDFLAGS=-mz80 --no-std-crt0\
+		--code-loc 0x8100\
+		--data-loc 0xC000\
+		--stack-loc 0x0000\
+		-Wl-b_GSINIT=0x8080
+
+all : $(TARGET)
+
+$(OBJ): | $(BUILD)
+
+$(BUILD) :
+	@mkdir -p $(BUILD)
+
+$(BUILD)/%.rel : %.asm
+	@echo '  (AS)' $<
+	@$(CPP) -P -I$(INCLUDE) -DASSEMBLY $< > $(BUILD)/$(notdir $<)
+	@$(AS) -g -o $@ $(BUILD)/$(notdir $<)
+
+$(BUILD)/%.rel : %.c
+	@echo '  (CC)' $<
+	@$(CC) $(CFLAGS) -c -o $@ $<
+
+$(IHX) : $(OBJ)
+	@echo '  (LD)' $(OBJ)
+	@$(CC) $(LDFLAGS) -o $@ $(OBJ)
+
+$(TARGET) : $(IHX)
+	@hex2bin.py $< $@
+
+.PHONY : clean
+clean :
+	@find $(BUILD) -type f -delete
diff --git a/boot/bootloader.c b/boot/bootloader.c
new file mode 100644
index 0000000..042414b
--- /dev/null
+++ b/boot/bootloader.c
@@ -0,0 +1,376 @@
+#include <hardware.h>
+#include <zeta.h>
+#include <fifo.h>
+
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+
+#ifdef __GNUC__
+#define PACKED __attribute__((packed))
+#else
+#define PACKED
+#endif
+
+u16
+crc16(const void *buf, size_t len);
+
+enum header_type {
+    CMD_PING,
+    CMD_INFO,
+    CMD_BOOT,
+    CMD_READ,
+    CMD_WRITE,
+    CMD_IO_READ,
+    CMD_IO_WRITE,
+    CMD_ECHO
+};
+
+struct header {
+    u8 type;
+    u8 bank;
+    u16 address;
+    u16 length;
+    u16 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
+
+u16
+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;
+
+u8
+getbyte(void)
+{
+    u8 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
+u8
+encode(u8 x)
+{
+    u8 y = 0;
+    const u8 c[4] = {0x61, 0x52, 0x34, 0x78};
+
+    for (u8 i = 0; i < 4; ++i)
+        y ^= ((x >> i) & 1) ? c[i] : 0;
+
+    return y;
+}
+
+// Hamming(7,4) decoding
+u8
+decode(u8 x)
+{
+    u8 p = 0;
+    const u8 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)
+{
+    u8 b;
+    u8 *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 u8 *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;
+    u8 ack;
+    u16 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;
+    u8 ack;
+    u16 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;
+    u8 ack = NACK;
+    u16 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
+loop(void)
+{
+    struct header header;
+    u8 buf[MAX_PACKET_SIZE];
+
+    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();
+    }
+}
+
+static inline void
+init_ctc(void)
+{
+	ctc_channel_0 = CTC_CTRL(0);
+
+	/* 200Hz clock */
+	ctc_channel_1 = CTC_CTRL(CTC_INT_BIT | CTC_PRESCALER_BIT
+							 | CTC_TIME_CONST_BIT | CTC_RST_BIT);
+	ctc_channel_1 = 0;
+
+	ctc_channel_2 = CTC_CTRL(0);
+	ctc_channel_3 = CTC_CTRL(0);
+
+	// Interrupt table for CTC
+	// Final address is (Ireg << 8) | ctc_isr_ptr | {00/01/10/11} | 0
+	ctc_channel_0 = CTC_INT_VEC(0x10);
+}
+
+static inline void
+init_pio(void)
+{
+	// Disable PIO interrupts
+	port_a_ctrl = PIO_INT_CTRL(0);
+	port_b_ctrl = PIO_INT_CTRL(0);
+}
+
+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
+		0x1C                            // 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];
+}
+
+void
+main(void)
+{
+	init_ctc();
+	init_pio();
+	init_sio();
+
+	IM(2);
+	EI;
+
+	loop();
+}
diff --git a/boot/crc16.c b/boot/crc16.c
new file mode 100644
index 0000000..ec7b015
--- /dev/null
+++ b/boot/crc16.c
@@ -0,0 +1,49 @@
+#include <zeta.h>
+#include <stddef.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/boot/crt0.asm b/boot/crt0.asm
new file mode 100644
index 0000000..09e4166
--- /dev/null
+++ b/boot/crt0.asm
@@ -0,0 +1,79 @@
+#include <hardware.h>
+    .module crt0
+    .globl  _main
+
+	.area	_HEADER (ABS)
+    .org    0x8000
+start:
+    di
+    ld      a, #0x80
+    ld      i, a
+    ld      sp, #0x0000
+    jr      main
+    .org    0x8010
+_ctc0_isr_ptr::
+    .dw     #0
+_ctc1_isr_ptr::
+    .dw     #_ctc1_isr
+_ctc2_isr_ptr::
+    .dw     #0
+_ctc3_isr_ptr::
+    .dw     #0
+_port_a_isr_ptr::
+    .dw     #0
+_port_b_isr_ptr::
+    .dw     #0
+_rx_isr_ptr::
+    .dw     #_rx_isr
+main:
+    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/include/hardware.h b/include/hardware.h
index 2e6c9da..7333328 100644
--- a/include/hardware.h
+++ b/include/hardware.h
@@ -17,6 +17,7 @@
 #define CTC_INT_BIT            0x80
 
 #define CTC_CTRL(x) ((x) | CTC_CTRL_OR_VECTOR_BIT)
+#define CTC_INT_VEC(x) ((x))
 
 // ********************************************************
 #define PORT_A_CTRL 0x42
@@ -75,6 +76,14 @@ __sfr __at(TFT_DATA) tft_data;
 #define IM(__mode) __asm__("im " #__mode)
 #define EI __asm__("ei")
 #define DI __asm__("di")
-#endif // ASSEMBLY
 
+#else
+#define KEYA 0x01
+#define KEYB 0x02
+#define KEY1 0x04
+#define KEY2 0x08
+#define KEY3 0x10
+#define KEY4 0x20
+#define KEY5 0x40
+#endif // ASSEMBLY
 #endif // HARDWARE_H
diff --git a/src/main.c b/src/main.c
index aff1329..8d9eb19 100644
--- a/src/main.c
+++ b/src/main.c
@@ -25,33 +25,25 @@ init_pio(void)
 	// A, B and five keys as inputs
 	port_b_ctrl = 0x7F;
 	// Load interrupt vector
-	//  port_b_ctrl = ISR_ADDRESS(port_b_isr_ptr);
+	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);
+    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_b_ctrl = 0x80;
 
+	// Control mode - i.e. no parallel port communication
 	/* 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 */
+	/* 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;
+	// Init CTC with known state (disable posible non-defined interrupts)
+	ctc_channel_0 = CTC_CTRL(0);
+	ctc_channel_1 = CTC_CTRL(0);
 
 	/* 200Hz clock */
 	ctc_channel_2 = CTC_CTRL(CTC_INT_BIT | CTC_PRESCALER_BIT
@@ -136,12 +128,6 @@ main(void)
     EI;
 
 	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)