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@hadleyrich
Created May 27, 2014 00:10
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/*
* Example of how to use the avr-libc EEPROM functions;
* http://www.nongnu.org/avr-libc/user-manual/group__avr__eeprom.html
*
*/
#define F_CPU 32000000
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/eeprom.h>
#include <util/delay.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "usart.h"
#include "clock.h"
#define EXPECTED_MAGIC 27
#define STRING_LEN 13
uint8_t eeprom_magic_byte EEMEM = 0;
uint16_t eeprom_big EEMEM = 0;
uint32_t eeprom_bigger EEMEM = 0;
char eeprom_string[STRING_LEN] EEMEM = "";
uint8_t magic_byte = 0;
uint16_t big = 0;
uint32_t bigger = 0;
char string[STRING_LEN] = "";
int main(void) {
sysclk_init();
sei();
// configure the usart1 (attached to USB) for 9600,8,N,1 to
// show debugging info, see usart examples for explanation
usart_init(1, 128, 128);
usart_conf(1, 9600, 8, none, 1, 0, NULL);
usart_map_stdio(1);
usart_run(1);
// wait for EEPROM to be ready
eeprom_busy_wait();
// Delay to give time for you to open a terminal and see the output
_delay_ms(2000);
// read magic byte from EEPROM to see if we've ever run before
magic_byte = eeprom_read_byte(&eeprom_magic_byte); // single byte
if (magic_byte != EXPECTED_MAGIC) {
puts("No magic found, setting values to defaults.\r");
puts("Reset your Kakapo to run again.\r");
magic_byte = EXPECTED_MAGIC;
big = 12345;
bigger = 1234567890UL;
strncpy(string, "Hello World!\0", STRING_LEN);
// update values to EEPROM
// the _update_ functions will test whether the existing EEPROM value is the same
// before writing to save flash wear, there are also _write_ functions which do not
eeprom_update_byte(&eeprom_magic_byte, magic_byte);
eeprom_update_word(&eeprom_big, big);
eeprom_update_dword(&eeprom_bigger, bigger);
eeprom_update_block((void*)&string, (void*)&eeprom_string, STRING_LEN);
} else {
puts("Magic found, reading values from EEPROM;\r");
big = eeprom_read_word(&eeprom_big); // word
bigger = eeprom_read_dword(&eeprom_bigger); // long integer
eeprom_read_block((void*)&string, (void*)&eeprom_string, STRING_LEN); // char array
_delay_ms(100);
printf("magic_byte = %u\r\n", magic_byte);
printf("big = %u\r\n", big);
printf("bigger = %lu\r\n", bigger);
printf("string = %s\r\n", string);
}
puts("========================\r\n");
_delay_ms(100); // let the characters go out the usart
return 0;
}
# Where is the toolchain unpacked?
TOOLBASE ?= /usr/local/share/avr8-gnu-toolchain-linux_x86_64
# What MCU do we have on this board?
MCU ?= atxmega64d4
# Port that Kakapo popped up on
PORT ?= /dev/ttyUSB1
# Application name
APP = eeprom
# If using libkakapo, uncomment
LIBKAKAPO = -lkakapo
#Tools we'll need
CC = $(TOOLBASE)/bin/avr-gcc
AVRDUDE = /usr/bin/avrdude
OBJCOPY = $(TOOLBASE)/bin/avr-objcopy
CFLAGS = -Os --std=c99 -funroll-loops -funsigned-char -funsigned-bitfields -fpack-struct
CFLAGS += -fshort-enums -Wstrict-prototypes -Wall -mcall-prologues -I. -I../../
CFLAGS += -mmcu=$(MCU)
INCLUDE = -L../../
OBJ = $(patsubst %.c,%.o,$(wildcard *.c))
build: $(APP).hex
eeprom: $(APP).eep
$(AVRDUDE) -p $(MCU) -c avr109 -P $(PORT) -b 115200 -U eeprom:w:$(APP).eep
program: $(APP).hex
$(AVRDUDE) -p $(MCU) -c avr109 -P $(PORT) -b 115200 -U flash:w:$(APP).hex -e
$(APP).hex: $(APP).elf
$(OBJCOPY) -O ihex -R .eeprom $< $@
$(APP).eep : $(APP).elf
$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
--change-section-lma .eeprom=0 -O ihex $< $@
$(APP).elf: $(OBJ)
$(CC) $(CFLAGS) $(INCLUDE) $^ -o $@ $(LIBKAKAPO)
%.o: %.c %.h Makefile
$(CC) -c $(CFLAGS) $< -o $@
clean:
rm -f $(OBJ) $(APP).hex $(APP).elf $(APP).eep
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