feat(ex00): done

.clang-format

@@ -0,0 +1,57 @@
+BasedOnStyle: Chromium
+AccessModifierOffset: 0
+AlignConsecutiveAssignments:
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+  AlignCompound: true
+  AlignFunctionPointers: true
+  PadOperators: true
+AlignConsecutiveMacros:
+  Enabled: true
+  AcrossEmptyLines: true
+  AcrossComments: true
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+  AlignFunctionPointers: true
+  PadOperators: true
+AlignConsecutiveShortCaseStatements:
+  Enabled: true
+  AcrossEmptyLines: true
+  AcrossComments: true
+  AlignCaseArrows: true
+  AlignCaseColons: true
+ColumnLimit: 100
+NamespaceIndentation: All
+CommentPragmas: ""
+IncludeCategories:
+  - Regex: ^<.*\.h>
+    Priority: 1
+    SortPriority: 0
+    CaseSensitive: false
+  - Regex: ^<.*
+    Priority: 2
+    SortPriority: 0
+    CaseSensitive: false
+  - Regex: .*
+    Priority: 3
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+IndentPPDirectives: AfterHash
+IndentWidth: 4
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+UseTab: Always
+Language: Cpp
+IndentAccessModifiers: true

.gitignore

@@ -0,0 +1,8 @@
+*.o
+*.hex
+*.bin
+*.elf
+build/
+/avr-libc
+compile_commands.json
+.cache/

ex00/Makefile

@@ -0,0 +1,54 @@
+# Makefile
+MCU=atmega328p
+F_CPU=16000000
+CC=avr-gcc
+OBJCOPY=avr-objcopy
+CFLAGS=-std=c99 -Wall -Wextra -g -Os -mmcu=$(MCU) -DF_CPU=$(F_CPU) -Iinclude
+IFLAGS=
+TARGET=main
+SERIAL=-P /dev/ttyUSB0 -b 115200
+
+SRC_DIR=src
+OBJ_DIR=build
+
+SRC_FILES=main.c utils.c uart.c
+OBJ_FILES=$(patsubst %.c,%.o,$(SRC_FILES))
+
+SRC=$(addprefix $(SRC_DIR)/,$(SRC_FILES))
+OBJ=$(addprefix $(OBJ_DIR)/,$(OBJ_FILES))
+
+ELF_FILE=$(OBJ_DIR)/$(TARGET).elf
+HEX_FILE=$(OBJ_DIR)/$(TARGET).hex
+
+all: flash
+
+re: fclean all
+
+fclean: clean
+	rm -f $(HEX_FILE)
+	rm -f $(ELF_FILE)
+clean:
+	rm -rf $(OBJ_DIR)
+
+hex: $(HEX_FILE)
+
+flash: hex
+	avrdude -p $(MCU) -c arduino -U flash:w:$(HEX_FILE):i $(SERIAL) 
+
+
+$(OBJ_DIR)/%.o: $(SRC_DIR)/%.c 
+	@mkdir -p $(shell dirname $@)
+	$(CC) $(CFLAGS) $(IFLAGS) -c $< -o $@
+
+$(ELF_FILE): $(OBJ)
+	$(CC) $(CFLAGS) $(OBJ) -o $@
+
+$(HEX_FILE): $(ELF_FILE)
+	$(OBJCOPY) -j .text -j .data -O ihex $< $@
+
+print:
+	@echo $(SRC)
+	@echo $(OBJ)
+	@echo $(ELF_FILE)
+	@echo $(HEX_FILE)
+

ex00/include/interupt.h

@@ -0,0 +1,14 @@
+#ifndef INTERUPT_H
+#define INTERUPT_H
+
+#include <avr/io.h>
+
+static inline void my_sei(void) {
+	SREG |= _BV(SREG_I);
+}
+
+static inline void my_cli(void) {
+	SREG &= ~_BV(SREG_I);
+}
+
+#endif /* INTERUPT_H */

ex00/include/mystd.h

@@ -0,0 +1,17 @@
+#ifndef MYSTDINT_H
+#define MYSTDINT_H
+
+typedef unsigned int uint16_t;
+typedef signed int	 int16_t;
+
+typedef unsigned char uint8_t;
+typedef signed char	  int8_t;
+
+typedef uint8_t bool;
+
+#define true  (1)
+#define false (0)
+
+#define NULL ((void*)0)
+
+#endif /* MYSTDINT_H */

ex00/include/timer0.h

@@ -0,0 +1,112 @@
+#ifndef TIMER0_H
+#	define TIMER0_H
+
+#	include <avr/io.h>
+#	include "mystd.h"
+
+#	include "timer_global.h"
+
+static inline void t0_init_fpwm_3(e_timer_prescaler prescaler) {
+	// Fast PWM (8-bit): WGM22:0 = 0b011
+	TCCR0A	= _BV(WGM00) | _BV(WGM01);
+
+	// reset to zero -> timer off
+	TCCR0B &= ~(_BV(CS02) | _BV(CS01) | _BV(CS00));
+	// set the correct prescaler
+	switch (prescaler) {
+		case (PRESCALER_1): {
+			TCCR0B |= (_BV(CS00));
+			break;
+		}
+		case (PRESCALER_8): {
+			TCCR0B |= (_BV(CS01));
+			break;
+		}
+		case (PRESCALER_64): {
+			TCCR0B |= (_BV(CS01) | _BV(CS00));
+			break;
+		}
+		case (PRESCALER_256): {
+			TCCR0B |= (_BV(CS02));
+			break;
+		}
+		case (PRESCALER_1024): {
+			TCCR0B |= (_BV(CS02) | _BV(CS00));
+			break;
+		}
+		case (PRESCALER_OFF): {
+			break;
+		}
+	}
+}
+
+static inline void t0_set_ocr(enum e_timer_output output, uint8_t value) {
+	if (output & TO_A)
+		OCR0A = value;
+	if (output & TO_B)
+		OCR0B = value;
+}
+
+static inline void t0_set_out_mode(enum e_timer_output output, enum e_timer_output_mode mode) {
+	if (output & TO_A) {
+		TCCR0A &= ~(_BV(COM0A1) | _BV(COM0A0));
+		switch (mode) {
+			case (TOM_00): {
+				break;
+			}
+			case (TOM_10): {
+				TCCR0A |= (_BV(COM0A1));
+				break;
+			}
+			case (TOM_01): {
+				TCCR0A |= (_BV(COM0A0));
+				break;
+			}
+			case (TOM_11): {
+				TCCR0A |= (_BV(COM0A1) | _BV(COM0A0));
+				break;
+			}
+		}
+	}
+	if (output & TO_B) {
+		TCCR0A &= ~(_BV(COM0B1) | _BV(COM0B0));
+		switch (mode) {
+			case (TOM_00): {
+				break;
+			}
+			case (TOM_10): {
+				TCCR0A |= (_BV(COM0B1));
+				break;
+			}
+			case (TOM_01): {
+				TCCR0A |= (_BV(COM0B0));
+				break;
+			}
+			case (TOM_11): {
+				TCCR0A |= (_BV(COM0B1) | _BV(COM0B0));
+				break;
+			}
+		}
+	}
+}
+
+// OC2B => RED   => PD3
+// OC0B => GREEN => PD5
+// OC0A => BLUE  => PD6
+
+#endif /* TIMER0_H */
+
+	/*
+		// OC2B = PD3 → output
+		DDRD   |= _BV(DDD3) | _BV(DDD5) | _BV(DDD6);
+
+		// Fast PWM (8-bit): WGM22:0 = 0b011
+		TCCR0A	= _BV(WGM00) | _BV(WGM01);
+		TCCR0A |= _BV(COM0B1);
+
+		// 50% duty cycle
+		OCR0B	= 128;
+
+		// Start timer, prescaler = 64
+		TCCR0B	= _BV(CS02);
+	*/

ex00/include/timer2.h

@@ -0,0 +1,112 @@
+#ifndef TIMER2_H
+#	define TIMER2_H
+
+#	include <avr/io.h>
+#	include "mystd.h"
+
+#	include "timer_global.h"
+
+static inline void t2_init_fpwm_3(e_timer_prescaler prescaler) {
+	// Fast PWM (8-bit): WGM22:0 = 0b011
+	TCCR2A	= _BV(WGM20) | _BV(WGM21);
+
+	// reset to zero -> timer off
+	TCCR2B &= ~(_BV(CS22) | _BV(CS21) | _BV(CS20));
+	// set the correct prescaler
+	switch (prescaler) {
+		case (PRESCALER_1): {
+			TCCR2B |= (_BV(CS20));
+			break;
+		}
+		case (PRESCALER_8): {
+			TCCR2B |= (_BV(CS21));
+			break;
+		}
+		case (PRESCALER_64): {
+			TCCR2B |= (_BV(CS21) | _BV(CS20));
+			break;
+		}
+		case (PRESCALER_256): {
+			TCCR2B |= (_BV(CS22));
+			break;
+		}
+		case (PRESCALER_1024): {
+			TCCR2B |= (_BV(CS22) | _BV(CS20));
+			break;
+		}
+		case (PRESCALER_OFF): {
+			break;
+		}
+	}
+}
+
+static inline void t2_set_ocr(enum e_timer_output output, uint8_t value) {
+	if (output & TO_A)
+		OCR2A = value;
+	if (output & TO_B)
+		OCR2B = value;
+}
+
+static inline void t2_set_out_mode(enum e_timer_output output, enum e_timer_output_mode mode) {
+	if (output & TO_A) {
+		TCCR2A &= ~(_BV(COM2A1) | _BV(COM2A0));
+		switch (mode) {
+			case (TOM_00): {
+				break;
+			}
+			case (TOM_10): {
+				TCCR2A |= (_BV(COM2A1));
+				break;
+			}
+			case (TOM_01): {
+				TCCR2A |= (_BV(COM2A0));
+				break;
+			}
+			case (TOM_11): {
+				TCCR2A |= (_BV(COM2A1) | _BV(COM2A0));
+				break;
+			}
+		}
+	}
+	if (output & TO_B) {
+		TCCR2A &= ~(_BV(COM2B1) | _BV(COM2B0));
+		switch (mode) {
+			case (TOM_00): {
+				break;
+			}
+			case (TOM_10): {
+				TCCR2A |= (_BV(COM2B1));
+				break;
+			}
+			case (TOM_01): {
+				TCCR2A |= (_BV(COM2B0));
+				break;
+			}
+			case (TOM_11): {
+				TCCR2A |= (_BV(COM2B1) | _BV(COM2B0));
+				break;
+			}
+		}
+	}
+}
+
+// OC2B => RED   => PD3
+// OC0B => GREEN => PD5
+// OC0A => BLUE  => PD6
+
+#endif /* TIMER0_H */
+
+	/*
+		// OC2B = PD3 → output
+		DDRD   |= _BV(DDD3) | _BV(DDD5) | _BV(DDD6);
+
+		// Fast PWM (8-bit): WGM22:0 = 0b011
+		TCCR2A	= _BV(GM20) | _BV(GM21);
+		TCCR2A |= _BV(COM2B1);
+
+		// 50% duty cycle
+		OCR0B	= 128;
+
+		// Start timer, prescaler = 64
+		TCCR2B	= _BV(CS22);
+	*/

ex00/include/timer_global.h

@@ -0,0 +1,25 @@
+#ifndef TIMER_GLOBAL_H
+#define TIMER_GLOBAL_H
+
+typedef enum e_timer_prescaler {
+	PRESCALER_OFF  = 0,
+	PRESCALER_1	   = 1,
+	PRESCALER_8	   = 8,
+	PRESCALER_64   = 64,
+	PRESCALER_256  = 256,
+	PRESCALER_1024 = 1024,
+} e_timer_prescaler;
+
+typedef enum e_timer_output {
+	TO_A = (1 << 0),
+	TO_B = (1 << 1),
+} e_timer_output;
+
+typedef enum e_timer_output_mode {
+	TOM_00,
+	TOM_01,
+	TOM_10,
+	TOM_11,
+} e_timer_output_mode;
+
+#endif /* TIMER_GLOBAL_H */

ex00/include/uart.h

@@ -0,0 +1,19 @@
+#ifndef UART_H
+#define UART_H
+
+#include "mystd.h"
+
+void uart_init(void);
+
+void uart_tx(char data);
+void uart_sendstring(const char* str);
+
+void uart_send_u8(uint8_t val);
+void uart_send_u16(uint16_t val);
+
+void uart_send_u8_hex(uint8_t val);
+void uart_send_u16_hex(uint16_t val);
+
+char uart_rx(void);
+
+#endif /* UART_H */

ex00/include/utils.h

@@ -0,0 +1,12 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+#include "mystd.h"
+
+void delay_ms(uint16_t count);
+
+void ft_bzero(void *data, uint16_t size);
+
+uint8_t ft_stridx(const char* str, char chr);
+
+#endif /* UTILS_H */

ex00/src/main.c

@@ -0,0 +1,36 @@
+#include <avr/io.h>
+#include <util/delay.h>
+
+#include "interupt.h"
+#include "mystd.h"
+
+#include "uart.h"
+
+// interrupt for INT0 (external interrupt)
+void __attribute__((signal, used)) __vector_1(void) {
+	my_cli();
+	_delay_ms(20);
+	PORTB ^= _BV(PB0);
+	// clear the register "pending" bit
+	EIFR  |= _BV(INTF0);
+	my_sei();
+}
+
+int main(void) {
+	uart_init();
+
+	DDRB  |= _BV(PB0);
+	DDRD  &= ~_BV(PD2);
+
+	// Set INT0 to trigger on falling edge
+	EICRA &= ~(_BV(ISC00) | _BV(ISC01));
+	EICRA |= _BV(ISC01);
+
+	// yes we want the INT0 interupt !
+	EIMSK |= _BV(INT0);
+
+	my_sei();
+
+	while (1) {
+	}
+}

ex00/src/uart.c

@@ -0,0 +1,105 @@
+#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) | _BV(RXCIE0);
+
+	// 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);
+}
+*/

ex00/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;
+}