does not work

ex02/src/main.c

@@ -0,0 +1,79 @@
+#include <avr/io.h>
+#include <util/delay.h>
+
+#include "interupt.h"
+#include "mystd.h"
+
+#include "timer_global.h"
+#include "uart.h"
+
+#include "timer0.h"
+#include "timer1.h"
+#include "timer2.h"
+
+volatile uint8_t counter = 0;
+
+#define LED_MASK (_BV(PB0) | _BV(PB1) | _BV(PB2) | _BV(PB4));
+
+void display_counter(void) {
+	PORTB &= ~LED_MASK;
+	PORTB |= ((counter & 0b111) | ((counter & 0b1000) << 1));
+}
+
+// interrupt for INT0 (external interrupt)
+void __attribute__((signal, used)) __vector_1(void) {
+	EIMSK &= ~_BV(INT0);
+	EIFR  |= _BV(INTF0);
+	// clear the register "pending" bit
+	t1_interrupt(TO_A, true);
+	counter++;
+	display_counter();
+	// uart_tx('I');
+}
+
+// external interupt
+void __attribute__((signal, used)) __vector_5(void) {
+	EIMSK &= ~_BV(INT0);
+	EIFR  |= _BV(INTF0);
+	// clear the register "pending" bit
+	t1_interrupt(TO_A, true);
+	counter++;
+	display_counter();
+	// uart_tx('I');
+}
+
+// timer1 compare match A
+void __attribute__((signal, used)) __vector_11(void) {
+	static uint8_t prev_state = 0;
+}
+
+// timer1 overflow match B
+
+int main(void) {
+	uart_init();
+
+	t1_init_ctc_4(PRESCALER_1024);
+	t1_interrupt(TO_B, true);
+	t1_set_ocr(TO_A, (F_CPU / (1024 * 20)) - 1);
+
+	DDRB   |= LED_MASK;
+	DDRD   &= ~(_BV(PD2) | _BV(PD4));
+
+	// Set INT0 to trigger on falling edge
+	EICRA  &= ~(_BV(ISC00) | _BV(ISC01));
+	EICRA  |= _BV(ISC01);
+
+	// yes we want the INT0 interupt !
+	EIMSK  |= _BV(INT0);
+
+	// PD4
+	// Enable Pin Change Interrupt group for PORTD (PCINT[23:16])
+	PCICR  |= (1 << PCIE2);
+
+	// Enable interrupt specifically for PD4 (PCINT20)
+	PCMSK2 |= (1 << PCINT20);
+
+	my_sei();
+	while (1) {
+	}
+}

ex02/src/uart.c

@@ -0,0 +1,103 @@
+#include "uart.h"
+#include <avr/io.h>
+#include "mystd.h"
+#include "utils.h"
+
+#define BAUD_RATE  115200
+
+#define UBRR_VALUE ((F_CPU / (8UL * BAUD_RATE)) - 1)
+
+// uart is 115200 baud rate, 8 bits per word, no parrity and 1 stop bit
+// 115200 8N1
+void uart_init(void) {
+	// Set baud rate
+	UBRR0H	= (uint8_t)(UBRR_VALUE >> 8);
+	UBRR0L	= (uint8_t)(UBRR_VALUE);
+
+	UCSR0A |= _BV(U2X0);
+	// Enable transmitter
+	UCSR0B	= _BV(TXEN0) | _BV(RXEN0);
+
+	// Set frame format: 8 data bits, no parity, 1 stop bit
+	UCSR0C	= _BV(UCSZ01) | _BV(UCSZ00);
+
+	// Set TX (PD1) as output
+	DDRD   |= _BV(PD1);
+}
+
+void uart_tx(char data) {
+	// wait for transmit buffer to be empty
+	while (!(UCSR0A & _BV(UDRE0)))
+		;
+	// load data into transmit register
+	UDR0 = data;
+}
+
+char uart_rx(void) {
+	while (!(UCSR0A & _BV(RXC0)))
+		;
+	return UDR0;
+}
+
+void uart_sendstring(const char* str) {
+	if (!str)
+		return;
+	while (*str) {
+		uart_tx(*str);
+		str++;
+	}
+}
+void uart_send_u8(uint8_t val) {
+	char	buf[4]	= {0, 0, 0, 0};
+	uint8_t idx		= 0;
+	bool	print	= false;
+
+	uint8_t modulus = 100;
+	while (modulus) {
+		uint8_t digit = val / modulus;
+		if (print || digit != 0) {
+			print	   = true;
+			buf[idx++] = '0' + digit;
+		}
+		val		%= modulus;
+		modulus /= 10;
+	}
+
+	uart_sendstring(buf);
+}
+
+void uart_send_u16(uint16_t val) {
+	char	buf[6]	 = {0, 0, 0, 0, 0, 0};
+	uint8_t idx		 = 0;
+	bool	print	 = false;
+
+	uint16_t modulus = 10000;
+	while (modulus) {
+		uint8_t digit = val / modulus;
+		if (print || digit != 0) {
+			print	   = true;
+			buf[idx++] = '0' + digit;
+		}
+		val		%= modulus;
+		modulus /= 10;
+	}
+	uart_sendstring(buf);
+}
+
+void uart_send_u8_hex(uint8_t val) {
+	char buf[3] = {0, 0, 0};
+	buf[0]		= "0123456789abcdef"[(val >> 4) & 0x0F];
+	buf[1]		= "0123456789abcdef"[(val >> 0) & 0x0F];
+
+	uart_sendstring(buf);
+}
+
+void uart_send_u16_hex(uint16_t val) {
+	char buf[5] = {0, 0, 0, 0, 0};
+
+	buf[0]		= "0123456789abcdef"[(val >> 12) & 0x0F];
+	buf[1]		= "0123456789abcdef"[(val >> 8) & 0x0F];
+	buf[2]		= "0123456789abcdef"[(val >> 4) & 0x0F];
+	buf[3]		= "0123456789abcdef"[(val >> 0) & 0x0F];
+	uart_sendstring(buf);
+}

ex02/src/utils.c

@@ -0,0 +1,39 @@
+#include "utils.h"
+#include "mystd.h"
+
+// this just burns cycles.
+// the volatile is important, it means that the cpu can't optimize any
+// read/writes for the value
+static inline void spin_loop(volatile uint16_t counts) {
+	while (counts)
+		counts--;
+}
+
+void delay_ms(uint16_t ms) {
+	while (ms) {
+		// this value was taken using a delay of 500ms, and just recording the led
+		// blinking. it seems to be high enough such that each loop of delay_loop
+		// takes 1ms :D
+		spin_loop((F_CPU) / 5000);
+		ms--;
+	}
+}
+
+void ft_bzero(void* data, uint16_t size) {
+	char* d = data;
+	while (size) {
+		*d = 0;
+		d++;
+		size--;
+	}
+}
+
+uint8_t ft_stridx(const char* str, char chr) {
+	if (!str)
+		return -1;
+	for (uint8_t i = 0; str[i]; i++) {
+		if (str[i] == chr)
+			return i;
+	}
+	return -1;
+}