initial commit

A simple program that uses the avr-gcc environment with an arduino board.

Signed-off-by: Jeff Epler <jepler@unpythonic.net>

.gitignore

@@ -0,0 +1,10 @@
+Makefile.local
+*-stamp
+*.*##
+.*.sw?
+.sw?
+*.elf
+*.hex
+eagle/*-bom.txt
+eagle/*.erc
+eagle/*.pro

Makefile

@@ -0,0 +1,43 @@
+DEV := /dev/serial/by-id/usb-FTDI_FT232R_USB_UART_A9007N2c-if00-port0
+MCU := atmega328
+AMCU := m328p
+AVRDUDE := avrdude
+AVRDUDE += -p${AMCU} -c arduino -P ${DEV} -b57600
+
+# Place your settings here, such as overriding DEV
+-include Makefile.local
+
+ifeq ($(shell [ -e ${DEV} ] && echo 1),1)
+default: program-stamp
+else
+default: main.elf
+	echo "Board not detected, skipping programming step"
+endif
+
+# note: the arduino bootloader can't program eeprom
+program-stamp: program
+	touch $@
+
+program: main.hex
+	${AVRDUDE} -q -q -D -U flash:w:main.hex:i
+
+communicate:
+	screen ${DEV} 57600
+
+.PRECIOUS: %.hex
+%.hex: %.elf
+	avr-objcopy -O ihex -R eeprom $< $@
+
+.PRECIOUS: %.elf
+%.elf: %.cc
+	avr-gcc -funit-at-a-time -finline-functions-called-once -fno-exceptions -fno-rtti -mmcu=${MCU} -DF_CPU=16000000ull -O3 -g $< -o $@
+
+clean:	
+	rm -f main.elf main.hex
+
+.PHONY: default program clean communicate
+
+# Copying and distribution of this file, with or without modification,
+# are permitted in any medium without royalty provided the copyright
+# notice and this notice are preserved.  This file is offered as-is,
+# without any warranty.

main.cc

@@ -0,0 +1,53 @@
+#include <avr/interrupt.h>
+#include <avr/io.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <util/delay.h>
+#include <avr/pgmspace.h>
+
+#define PIN_LED (5) // onboard LED is PORTD5
+
+static int serial_putc(char c, FILE *stream) {
+    if (c == '\n') {
+        serial_putc('\r', stream);
+    }
+    loop_until_bit_is_set(UCSR0A, UDRE0);
+    UDR0 = c;
+    return 0;
+}
+
+static int serial_getc(FILE *stream) {
+    loop_until_bit_is_set(UCSR0A, RXC0); /* Wait until data exists. */
+    return UDR0;
+}
+
+void serial_install_stdio() {
+    static FILE uart_stdio;
+    fdev_setup_stream(&uart_stdio, serial_putc, serial_getc, _FDEV_SETUP_RW);
+    stdin = stdout = stderr = &uart_stdio;
+    
+#define BAUD 57600
+#include <util/setbaud.h>
+    UBRR0 = UBRR_VALUE;
+#if USE_2X    
+    UCSR0A |= (1<<U2X0);
+#else
+    UCSR0A &= ~(1<<U2X0);
+#endif
+    UCSR0C = (1<<UCSZ01) | (1<<UCSZ00); /* 8-bit data */
+    UCSR0B = (1<<RXEN0) | (1<<TXEN0);   /* enable transmitter and receiver */
+}
+
+int main() {
+    serial_install_stdio();
+    DDRD |= (1<<PIN_LED);
+    printf_P(PSTR("HELLO AVR - press any key to toggle LED.  characters will be echoed\n"));
+    while(1) { int c = getchar(); putchar(c); PINB = (1<<PIN_LED); }
+}
+
+/*
+Copying and distribution of this file, with or without modification,
+are permitted in any medium without royalty provided the copyright
+notice and this notice are preserved.  This file is offered as-is,
+without any warranty.
+*/