I2C EEPROM Library: AVR and AT24CXXX

sun_ge@yahoo.cn

Image i2c-eeprom

Project Origin

AVR's I2C bus is simple, easy to use, and a lot of I2C devices can be attached together. This I2C EEPROM access library was built for ATmega48 and AT24C128/256, may also work for other microcontroller or I2C EEPROM with a little change.

Hardware

Please see at24cxxx.h for details.

Source Code

Source contains: at24cxxx.h, at24cxxx.c, i2c-eeprom-test.c and Makefile.
It can be compiled and installed by AVR GNU Tools Chain.

I2C EEPROM Library Header: at24cxxx.h


/*
at24cxxx.h:

for at24c128/256, have been tested on at24c256 (32Kx8bit, PageSize=64bytes),
and atmega48(8MHzRC).

test hardware:
at24c256 <--> atmega48
A0-->GND
A1-->GND
GND-->GND
SDA----->SDA(PC4 of mega48)
     |
    1KOhm
     |
     V
    VCC

SCL----->SCL(PC5 of mega48)
     |
    1KOhm
     |
     V
    VCC

WP-->GND
VCC-->VCC
(VCC-->0.1uF-->GND)

references:
1)at24c128/256 datasheet.
2)atmega48 datasheet.
3)demo project of avr-libc-manual-1.4.0.
*/

#include <inttypes.h>
#include <stdlib.h>

#include <avr/io.h>
#include <util/twi.h>
/* for future enhancement*/
#include <avr/interrupt.h>

/* twi address for at24c128/256:
1 0 1 0 0 A1 A0 R/W
*/
#define SLA_W_24CXXX 0xA0
#define SLA_R_24CXXX 0xA1

/* use mega48 interal RC 8MHz/1=8MHz lfuse=0xe2*/
#define F_CPU 8000000UL

/* page size is 64 byte, and address word is 15 bit (at24c256)
   =high 7 bit(as first address word)+low 8 bit(as second address word). */
#define PAGE_SIZE 64

/* set prescaler to 1.(TWPS0,1=0)*/
#define TWI_PS 0

/* save value of TW_STATUS */
uint8_t twst;

void twi_init(void);
int ee24cxxx_write_page(uint16_t addr, int len, uint8_t *buf);
int ee24cxxx_write_bytes(uint16_t addr, int len, uint8_t *buf);
int ee24cxxx_read_bytes(uint16_t addr, int len, uint8_t *buf);

I2C EEPROM Library: at24cxxx.c


/*
at24cxxx.c:

definition of functions.
see at24cxxx.h for details.
*/

#include "at24cxxx.h"

void twi_init(void)
{
  /* set prescaler*/
  TWSR = TWI_PS;

#if F_CPU < 3600000UL
  TWBR = 10; /* smallest TWBR value. */
#else
  TWBR = (F_CPU / 100000UL - 16) / 2;
#endif
}

/* page write, return nbyte which have sent, otherwise return -1*/
int ee24cxxx_write_page(uint16_t addr, int len, uint8_t *buf)
{
  int rv=0; /* return value */
  uint16_t endaddr;

  /*if the rest space of page is sufficient to store len byte*/
  if ((addr + len) <= (addr | (PAGE_SIZE - 1)))
    endaddr = addr + len;
  /*else the rest space is deficient/insufficient/inadequate to store len byte*/
  else
    endaddr = (addr | (PAGE_SIZE - 1)) + 1;
  /*adjust len*/
  len = endaddr - addr;

 begin:
  TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); /* send start condition */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_REP_START: /* OK, but should not happen */
    case TW_START:
      break;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      return -1;
      /*do /not/ send stop condition becasue I have sent nothing.*/
    }
  
  TWDR = SLA_W_24CXXX;
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MT_SLA_ACK:
      break;
    case TW_MT_SLA_NACK: /* nack during select: device busy writing */
      goto begin;
    case TW_MT_ARB_LOST: /* re-arbitrate */
      goto begin;
    default:
      rv=-1;
      goto quit; /*must send stop condition*/
    }
  TWDR = addr>>8; /* first address word (high)*/
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MT_DATA_ACK:
      break;
    case TW_MT_DATA_NACK:
      goto quit;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      rv=-1;
      goto quit;
    }
  TWDR = addr&0x00ff; /*second address word (low)*/
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MT_DATA_ACK:
      break;
    case TW_MT_DATA_NACK:
      goto quit;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      rv=-1;
      goto quit;
    }
  
  for (; len > 0; len--)
    {
      /* the address word low 6 bits are internally incremented following
	 the receipt of each data word. --at24c128/256 datasheet.
      */
      TWDR = *buf; /* send a byte */
      buf++;
      TWCR = _BV(TWINT) | _BV(TWEN); /* start transmission */
      while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
      switch ((twst = TW_STATUS))
	{
	case TW_MT_DATA_NACK:
	  rv=-1;
	  goto quit;
	case TW_MT_DATA_ACK:
	  rv++;
	  break;
	default:
	  rv=-1;
	  goto quit;
	}
    }
  
 quit:
  TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN); /* send stop condition */
  return rv;
  
}

/* also use page write mode */
int ee24cxxx_write_bytes(uint16_t addr, int len, uint8_t *buf)
{
  int rv;
  int total=0;
  
  do
    {
      rv = ee24cxxx_write_page(addr, len, buf);
      /*
	1)rv==-1: error.
	2)rv==0: retry.
	3)rv<len: need to store the rest bytes to a new page.
	4)rv==len: all bytes have been stored in this page. so I can return now.
      */
      if(rv==-1)
	return -1;
      len -= rv;      
      addr += rv;
      buf += rv;
      total += rv;
    }
  while(len > 0);
  
  return total;
      
}

/*random/sequential read mode*/
int ee24cxxx_read_bytes(uint16_t addr, int len, uint8_t *buf)
{
  uint8_t twcr;
  int rv=0;
  
 begin:
  TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); /* send start condition */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_REP_START: /* OK, but should not happen */
    case TW_START:
      break;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      return -1;
      /*do /not/ send stop condition*/
    }
  
  TWDR = SLA_W_24CXXX;
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MT_SLA_ACK:
      break;
    case TW_MT_SLA_NACK: /* nack during select: device busy writing */
      goto begin;
    case TW_MT_ARB_LOST: /* re-arbitrate */
      goto begin;
    default:
      rv=-1;
      goto quit; /*return error and send stop condition*/
    }

  TWDR = addr>>8; /* first address word (high)*/
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MT_DATA_ACK:
      break;
    case TW_MT_DATA_NACK:
      goto quit;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      rv=-1;
      goto quit;
    }
  TWDR = addr&0x00ff; /*second address word (low)*/
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MT_DATA_ACK:
      break;
    case TW_MT_DATA_NACK:
      goto quit;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      rv=-1;
      goto quit;
    }
  

  /*Next cycle: master receiver mode*/
  TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN); /* send (rep.) start condition */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_START: /* OK, but should not happen */
    case TW_REP_START:
      break;
    case TW_MT_ARB_LOST:
      goto begin;
    default:
      rv=-1;
      goto quit;
    }
  
  TWDR = SLA_R_24CXXX;
  TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
  switch ((twst = TW_STATUS))
    {
    case TW_MR_SLA_ACK:
      break;
    case TW_MR_SLA_NACK:
      goto quit;
    case TW_MR_ARB_LOST:
      goto begin;
    default:
      rv=-1;
      goto quit;
    }

  /*
    1)len=1: after receiving a byte, the Master Receiver send NACK, then send stop.
    2)len>1: after receiving a byte, the Master Receiver send ACK, so the eeprom
    will send the following byte.
    about TWEA bit, see also at24c128/256 and atmega48 datasheet for details */  
  twcr = _BV(TWINT) | _BV(TWEN) | _BV(TWEA); /* MR send ACK */
  for(; len>0; len--)
    {
      if(len==1)
	twcr = _BV(TWINT) | _BV(TWEN); /* send NACK */
      
      TWCR=twcr; /* clear interrupt to start transmission */
      
      while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
      switch ((twst = TW_STATUS))
	{
	case TW_MR_DATA_NACK:
	  *buf = TWDR;
	  rv++;
	  len=0; /*just ensure*/
	  break;
	case TW_MR_DATA_ACK:
	  *buf = TWDR;
	  buf++;
	  rv++;
	  break;
	default:
	  rv=-1;
	  goto quit;
	  
	}
    }
 quit:
  TWCR = _BV(TWINT) | _BV(TWSTO) | _BV(TWEN); /* send stop condition */
  return rv;
  
}

Demo Program: i2c-eeprom-test.c


/*
i2c-eeprom-test.c

This file access the atmel eeprom through at24cxxx lib:
main() show the usage of eeprom functions 
and test by display the byte through the main loop.

see at24cxxx.h and this code for hardware details.
*/

#include "at24cxxx.h"

#include <inttypes.h>
#include <avr/io.h>
#include <avr/pgmspace.h>

/*must after F_CPU define*/
#include <util/delay.h>

/* Keep activated for 3 ms */
#define LIGHTED_TIME_ms 3

/* define the connection of each segment */
#define SEG_PORT PORTD
#define DDR_SEG_PORT DDRD
#define SEG_a PD0 //disp pin7
#define SEG_b PD1 //disp pin6
#define SEG_c PD2 //disp pin4
#define SEG_d PD3 //disp pin2
#define SEG_e PD4 //disp pin1
#define SEG_f PD5 //disp pin9
#define SEG_g PD6 //disp pin10
#define SEG_dp PD7 //disp pin5

/* define the common Anode scan port */
#define SCAN_PORT PORTB //to pin3 of each disp.
#define DDR_SCAN_PORT DDRB
/* 4 displayers numbered 0-3 from Left to Right */
#define DISP0 PB2
#define DISP1 PB3
#define DISP2 PB4
#define DISP3 PB5

/* 7 segment led display font.
from first to last is:
'0','1','2','3','4','5','6','7',
'8','9','A','b','C','d','E','F','.'(dot),' '(disp off)
*/
const unsigned char _7_seg_font[18] PROGMEM = {
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f),
  (1<<SEG_b)|(1<<SEG_c),
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_g)|(1<<SEG_e)|(1<<SEG_d),
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_g)|(1<<SEG_c)|(1<<SEG_d),
  (1<<SEG_f)|(1<<SEG_g)|(1<<SEG_b)|(1<<SEG_c),
  (1<<SEG_a)|(1<<SEG_f)|(1<<SEG_g)|(1<<SEG_c)|(1<<SEG_d),
  (1<<SEG_a)|(1<<SEG_f)|(1<<SEG_e)|(1<<SEG_d)|(1<<SEG_c)|(1<<SEG_g),
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c),
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g),
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c)|(1<<SEG_d)|(1<<SEG_f)|(1<<SEG_g),
  (1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g),
  (1<<SEG_c)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g),
  (1<<SEG_a)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f),
  (1<<SEG_b)|(1<<SEG_c)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_g),
  (1<<SEG_a)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g),
  (1<<SEG_a)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g),
  (1<<SEG_dp),
  0x00
};

/*
buffer structure:
buffer[m] (m=0,1,2,3) have contents of 0x00 to 0x0F;
buffer[n] (n=m+4, is 4,5,6,7) have content of 0x10 (with dot) 
or 0x11 (without dot).
buffer[t] (t=m+8, is 8,9,10,11) is not the index of fonts,
It is 0x00(disp off) or 0xFF(disp on).
*/

void init_disp(void)
{
  DDR_SEG_PORT |= ((1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g)|(1<<SEG_dp));
  DDR_SCAN_PORT |= ((1<<DISP0)|(1<<DISP1)|(1<<DISP2)|(1<<DISP3));
  SEG_PORT |= ((1<<SEG_a)|(1<<SEG_b)|(1<<SEG_c)|(1<<SEG_d)|(1<<SEG_e)|(1<<SEG_f)|(1<<SEG_g)|(1<<SEG_dp));
  SCAN_PORT &= ~((1<<DISP0)|(1<<DISP1)|(1<<DISP2)|(1<<DISP3));
}


int main (void)
{
  int i,j;
  uint8_t buffer[12];
  
  uint16_t addr;
  uint8_t buf_in[] = {39,40,41,42,177};
  uint8_t buf_out[5];
  uint8_t data_out;
  
  init_disp();
  
  twi_init();
  
  addr = 255+61;
  ee24cxxx_write_bytes(addr, 5, buf_in);

  /*seems can work fine without delay.*/
  //_delay_ms(10);

  ee24cxxx_read_bytes(addr, 5, buf_out);
  
  /* init buffer for correct display*/
  buffer[0]=0x00;
  buffer[4]=0x11;
  buffer[8]=0xFF;
    
  buffer[1]=0x00;
  buffer[5]=0x11;
  buffer[9]=0xFF;
    
  buffer[2]=0x00;
  buffer[6]=0x11;
  buffer[10]=0xFF;

  buffer[3]=0x00;
  buffer[7]=0x11;
  buffer[11]=0xFF;
  
  /* Display buffer that is approx. 4*3ms=12ms per frame.*/
  for (;;) {
    
    /* show buf_out one by one */
    if(++i%100 == 0)
      data_out=buf_out[j++%5];
    
    /* just show data_out of 4 bit dec number */
    buffer[0] = data_out/1000;
    buffer[1] = (data_out%1000)/100;
    buffer[2] = (data_out%100)/10;
    buffer[3] = data_out%10;
    
    SEG_PORT = ~((pgm_read_byte(_7_seg_font+buffer[0])|pgm_read_byte(_7_seg_font+buffer[4]))&buffer[8]);
    SCAN_PORT |= (1<<DISP0);
    _delay_ms(LIGHTED_TIME_ms);
    SCAN_PORT &= ~((1<<DISP0)|(1<<DISP1)|(1<<DISP2)|(1<<DISP3));
    
    SEG_PORT = ~((pgm_read_byte(_7_seg_font+buffer[1])|pgm_read_byte(_7_seg_font+buffer[5]))&buffer[9]);
    SCAN_PORT |= (1<<DISP1);
    _delay_ms(LIGHTED_TIME_ms);
    SCAN_PORT &= ~((1<<DISP0)|(1<<DISP1)|(1<<DISP2)|(1<<DISP3));
    
    SEG_PORT = ~((pgm_read_byte(_7_seg_font+buffer[2])|pgm_read_byte(_7_seg_font+buffer[6]))&buffer[10]);
    SCAN_PORT |= (1<<DISP2);
    _delay_ms(LIGHTED_TIME_ms);
    SCAN_PORT &= ~((1<<DISP0)|(1<<DISP1)|(1<<DISP2)|(1<<DISP3));
    
    SEG_PORT = ~((pgm_read_byte(_7_seg_font+buffer[3])|pgm_read_byte(_7_seg_font+buffer[7]))&buffer[11]);
    SCAN_PORT |= (1<<DISP3);
    _delay_ms(LIGHTED_TIME_ms);
    SCAN_PORT &= ~((1<<DISP0)|(1<<DISP1)|(1<<DISP2)|(1<<DISP3));
    
  }
	
}

Makefile


# Hey Emacs, this is a -*- makefile -*-
#
# WinAVR Sample makefile written by Eric B. Weddington, Jörg Wunsch, et al.
# Released to the Public Domain
# Please read the make user manual!
#
# Additional material for this makefile was submitted by:
#  Tim Henigan
#  Peter Fleury
#  Reiner Patommel
#  Sander Pool
#  Frederik Rouleau
#  Markus Pfaff
#
# On command line:
#
# make all = Make software.
#
# make clean = Clean out built project files.
#
# make coff = Convert ELF to AVR COFF (for use with AVR Studio 3.x or VMLAB).
#
# make extcoff = Convert ELF to AVR Extended COFF (for use with AVR Studio
#                4.07 or greater).
#
# make program = Download the hex file to the device, using avrdude.  Please
#                customize the avrdude settings below first!
#
# make filename.s = Just compile filename.c into the assembler code only
#
# To rebuild project do "make clean" then "make all".
#


# MCU name
MCU = atmega48

# Output format. (can be srec, ihex, binary)
FORMAT = ihex

# Target file name (without extension).
TARGET = i2c-eeprom-test


# List C source files here. (C dependencies are automatically generated.)
SRC = $(TARGET).c

SRC += at24cxxx.c
# output from the compiler), and will be deleted upon "make clean"!
# Even though the DOS/Win* filesystem matches both .s and .S the same,
# it will preserve the spelling of the filenames, and gcc itself does
# care about how the name is spelled on its command-line.
ASRC = 



# Optimization level, can be [0, 1, 2, 3, s]. 
# 0 = turn off optimization. s = optimize for size.
# (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
OPT = s

# Debugging format.
# Native formats for AVR-GCC's -g are stabs [default], or dwarf-2.
# AVR (extended) COFF requires stabs, plus an avr-objcopy run.
DEBUG = stabs

# List any extra directories to look for include files here.
#     Each directory must be seperated by a space.
EXTRAINCDIRS = 


# Compiler flag to set the C Standard level.
# c89   - "ANSI" C
# gnu89 - c89 plus GCC extensions
# c99   - ISO C99 standard (not yet fully implemented)
# gnu99 - c99 plus GCC extensions
CSTANDARD = -std=gnu99

# Place -D or -U options here
CDEFS =

# Place -I options here
CINCS =


# Compiler flags.
#  -g*:          generate debugging information
#  -O*:          optimization level
#  -f...:        tuning, see GCC manual and avr-libc documentation
#  -Wall...:     warning level
#  -Wa,...:      tell GCC to pass this to the assembler.
#    -adhlns...: create assembler listing
CFLAGS = -g$(DEBUG)
CFLAGS += $(CDEFS) $(CINCS)
CFLAGS += -O$(OPT)
CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
CFLAGS += -Wall -Wstrict-prototypes
CFLAGS += -Wa,-adhlns=$(<:.c=.lst)
CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
CFLAGS += $(CSTANDARD)



# Assembler flags.
#  -Wa,...:   tell GCC to pass this to the assembler.
#  -ahlms:    create listing
#  -gstabs:   have the assembler create line number information; note that
#             for use in COFF files, additional information about filenames
#             and function names needs to be present in the assembler source
#             files -- see avr-libc docs [FIXME: not yet described there]
ASFLAGS = -Wa,-adhlns=$(<:.S=.lst),-gstabs 



#Additional libraries.

# Minimalistic printf version
PRINTF_LIB_MIN = -Wl,-u,vfprintf -lprintf_min

# Floating point printf version (requires MATH_LIB = -lm below)
PRINTF_LIB_FLOAT = -Wl,-u,vfprintf -lprintf_flt

PRINTF_LIB = 

# Minimalistic scanf version
SCANF_LIB_MIN = -Wl,-u,vfscanf -lscanf_min

# Floating point + %[ scanf version (requires MATH_LIB = -lm below)
SCANF_LIB_FLOAT = -Wl,-u,vfscanf -lscanf_flt

SCANF_LIB = 

MATH_LIB = -lm

# External memory options

# 64 KB of external RAM, starting after internal RAM (ATmega128!),
# used for variables (.data/.bss) and heap (malloc()).
#EXTMEMOPTS = -Wl,-Tdata=0x801100,--defsym=__heap_end=0x80ffff

# 64 KB of external RAM, starting after internal RAM (ATmega128!),
# only used for heap (malloc()).
#EXTMEMOPTS = -Wl,--defsym=__heap_start=0x801100,--defsym=__heap_end=0x80ffff

EXTMEMOPTS =

# Linker flags.
#  -Wl,...:     tell GCC to pass this to linker.
#    -Map:      create map file
#    --cref:    add cross reference to  map file
LDFLAGS = -Wl,-Map=$(TARGET).map,--cref
LDFLAGS += $(EXTMEMOPTS)
LDFLAGS += $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB)




# Programming support using avrdude. Settings and variables.

# Programming hardware: alf avr910 avrisp bascom bsd 
# dt006 pavr picoweb pony-stk200 sp12 stk200 stk500
#
# Type: avrdude -c ?
# to get a full listing.
#
#AVRDUDE_PROGRAMMER = stk500
AVRDUDE_PROGRAMMER = stk500v2

# com1 = serial port. Use lpt1 to connect to parallel port.
AVRDUDE_PORT = /dev/ttyUSB0    # programmer connected to serial device

AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex
#AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep


# Uncomment the following if you want avrdude's erase cycle counter.
# Note that this counter needs to be initialized first using -Yn,
# see avrdude manual.
#AVRDUDE_ERASE_COUNTER = -y

# Uncomment the following if you do /not/ wish a verification to be
# performed after programming the device.
#AVRDUDE_NO_VERIFY = -V

# Increase verbosity level.  Please use this when submitting bug
# reports about avrdude. See <http://savannah.nongnu.org/projects/avrdude> 
# to submit bug reports.
#AVRDUDE_VERBOSE = -v -v

AVRDUDE_FLAGS = -p $(MCU) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER)
AVRDUDE_FLAGS += $(AVRDUDE_NO_VERIFY)
AVRDUDE_FLAGS += $(AVRDUDE_VERBOSE)
AVRDUDE_FLAGS += $(AVRDUDE_ERASE_COUNTER)



# ---------------------------------------------------------------------------

# Define directories, if needed.
DIRAVR = c:/winavr
DIRAVRBIN = $(DIRAVR)/bin
DIRAVRUTILS = $(DIRAVR)/utils/bin
DIRINC = .
DIRLIB = $(DIRAVR)/avr/lib


# Define programs and commands.
SHELL = sh
CC = avr-gcc
OBJCOPY = avr-objcopy
OBJDUMP = avr-objdump
SIZE = avr-size
NM = avr-nm
AVRDUDE = avrdude
REMOVE = rm -f
COPY = cp




# Define Messages
# English
MSG_ERRORS_NONE = Errors: none
MSG_BEGIN = -------- begin --------
MSG_END = --------  end  --------
MSG_SIZE_BEFORE = Size before: 
MSG_SIZE_AFTER = Size after:
MSG_COFF = Converting to AVR COFF:
MSG_EXTENDED_COFF = Converting to AVR Extended COFF:
MSG_FLASH = Creating load file for Flash:
MSG_EEPROM = Creating load file for EEPROM:
MSG_EXTENDED_LISTING = Creating Extended Listing:
MSG_SYMBOL_TABLE = Creating Symbol Table:
MSG_LINKING = Linking:
MSG_COMPILING = Compiling:
MSG_ASSEMBLING = Assembling:
MSG_CLEANING = Cleaning project:




# Define all object files.
OBJ = $(SRC:.c=.o) $(ASRC:.S=.o) 

# Define all listing files.
LST = $(ASRC:.S=.lst) $(SRC:.c=.lst)


# Compiler flags to generate dependency files.
GENDEPFLAGS = -Wp,-M,-MP,-MT,$(*F).o,-MF,.dep/$(@F).d


# Combine all necessary flags and optional flags.
# Add target processor to flags.
ALL_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS) $(GENDEPFLAGS)
ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS)





# Default target.
all: begin gccversion sizebefore build sizeafter finished end

build: elf hex eep lss sym

elf: $(TARGET).elf
hex: $(TARGET).hex
eep: $(TARGET).eep
lss: $(TARGET).lss 
sym: $(TARGET).sym



# Eye candy.
# AVR Studio 3.x does not check make's exit code but relies on
# the following magic strings to be generated by the compile job.
begin:
	@echo
	@echo $(MSG_BEGIN)

finished:
	@echo $(MSG_ERRORS_NONE)

end:
	@echo $(MSG_END)
	@echo


# Display size of file.
HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
ELFSIZE = $(SIZE) -A $(TARGET).elf
sizebefore:
	@if [ -f $(TARGET).elf ]; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); echo; fi

sizeafter:
	@if [ -f $(TARGET).elf ]; then echo; echo $(MSG_SIZE_AFTER); $(ELFSIZE); echo; fi



# Display compiler version information.
gccversion : 
	@$(CC) --version



# Program the device.  
program: $(TARGET).hex $(TARGET).eep
	$(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_WRITE_FLASH) $(AVRDUDE_WRITE_EEPROM)




# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
COFFCONVERT=$(OBJCOPY) --debugging \
--change-section-address .data-0x800000 \
--change-section-address .bss-0x800000 \
--change-section-address .noinit-0x800000 \
--change-section-address .eeprom-0x810000 


coff: $(TARGET).elf
	@echo
	@echo $(MSG_COFF) $(TARGET).cof
	$(COFFCONVERT) -O coff-avr $< $(TARGET).cof


extcoff: $(TARGET).elf
	@echo
	@echo $(MSG_EXTENDED_COFF) $(TARGET).cof
	$(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof



# Create final output files (.hex, .eep) from ELF output file.
%.hex: %.elf
	@echo
	@echo $(MSG_FLASH) $@
	$(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@

%.eep: %.elf
	@echo
	@echo $(MSG_EEPROM) $@
	-$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
	--change-section-lma .eeprom=0 -O $(FORMAT) $< $@

# Create extended listing file from ELF output file.
%.lss: %.elf
	@echo
	@echo $(MSG_EXTENDED_LISTING) $@
	$(OBJDUMP) -h -S $< > $@

# Create a symbol table from ELF output file.
%.sym: %.elf
	@echo
	@echo $(MSG_SYMBOL_TABLE) $@
	$(NM) -n $< > $@



# Link: create ELF output file from object files.
.SECONDARY : $(TARGET).elf
.PRECIOUS : $(OBJ)
%.elf: $(OBJ)
	@echo
	@echo $(MSG_LINKING) $@
	$(CC) $(ALL_CFLAGS) $(OBJ) --output $@ $(LDFLAGS)


# Compile: create object files from C source files.
%.o : %.c
	@echo
	@echo $(MSG_COMPILING) $<
	$(CC) -c $(ALL_CFLAGS) $< -o $@ 


# Compile: create assembler files from C source files.
%.s : %.c
	$(CC) -S $(ALL_CFLAGS) $< -o $@


# Assemble: create object files from assembler source files.
%.o : %.S
	@echo
	@echo $(MSG_ASSEMBLING) $<
	$(CC) -c $(ALL_ASFLAGS) $< -o $@



# Target: clean project.
clean: begin clean_list finished end

clean_list :
	@echo
	@echo $(MSG_CLEANING)
	$(REMOVE) $(TARGET).hex
	$(REMOVE) $(TARGET).eep
	$(REMOVE) $(TARGET).obj
	$(REMOVE) $(TARGET).cof
	$(REMOVE) $(TARGET).elf
	$(REMOVE) $(TARGET).map
	$(REMOVE) $(TARGET).obj
	$(REMOVE) $(TARGET).a90
	$(REMOVE) $(TARGET).sym
	$(REMOVE) $(TARGET).lnk
	$(REMOVE) $(TARGET).lss
	$(REMOVE) $(OBJ)
	$(REMOVE) $(LST)
	$(REMOVE) $(SRC:.c=.s)
	$(REMOVE) $(SRC:.c=.d)
	$(REMOVE) .dep/*



# Include the dependency files.
-include $(shell mkdir .dep 2>/dev/null) $(wildcard .dep/*)


# Listing of phony targets.
.PHONY : all begin finish end sizebefore sizeafter gccversion \
build elf hex eep lss sym coff extcoff \
clean clean_list program



sun ge 2007-10-25