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avrdude
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avrdude/bitbang.c

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/*
* avrdude - A Downloader/Uploader for AVR device programmers
* Copyright (C) 2000, 2001, 2002, 2003 Brian S. Dean <bsd@bsdhome.com>
* Copyright (C) 2005 Michael Holzt <kju-avr@fqdn.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* $Id$ */
#include "ac_cfg.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#if !defined(WIN32NATIVE)
# include <signal.h>
# include <sys/time.h>
#endif
#include "avr.h"
#include "pindefs.h"
#include "pgm.h"
#include "par.h"
#include "serbb.h"
extern char * progname;
extern int do_cycles;
extern int verbose;
static int delay_decrement;
#if !defined(WIN32NATIVE)
static volatile int done;
typedef void (*mysighandler_t)(int);
static mysighandler_t saved_alarmhandler;
static void alarmhandler(int signo)
{
done = 1;
signal(SIGALRM, saved_alarmhandler);
}
#endif /* !WIN32NATIVE */
/*
* Calibrate the microsecond delay loop below.
*/
static void bitbang_calibrate_delay(void)
{
/*
* Right now, we don't have any Win32 implementation for this, so we
* can only run on a preconfigured delay stepping there. The figure
* below should at least be correct within an order of magnitude,
* judging from the auto-calibration figures seen on various Unix
* systems on comparable hardware.
*/
#if defined(WIN32NATIVE)
delay_decrement = 100;
#else /* !WIN32NATIVE */
struct itimerval itv;
volatile int i;
if (verbose >= 2)
fprintf(stderr,
"%s: Calibrating delay loop...",
progname);
i = 0;
done = 0;
saved_alarmhandler = signal(SIGALRM, alarmhandler);
/*
* Set ITIMER_REAL to 100 ms. All known systems have a timer
* granularity of 10 ms or better, so counting the delay cycles
* accumulating over 100 ms should give us a rather realistic
* picture, without annoying the user by a lengthy startup time (as
* an alarm(1) would do). Of course, if heavy system activity
* happens just during calibration but stops before the remaining
* part of AVRDUDE runs, this will yield wrong values. There's not
* much we can do about this.
*/
itv.it_value.tv_sec = 0;
itv.it_value.tv_usec = 100000;
itv.it_interval.tv_sec = itv.it_interval.tv_usec = 0;
setitimer(ITIMER_REAL, &itv, 0);
while (!done)
i--;
itv.it_value.tv_sec = itv.it_value.tv_usec = 0;
setitimer(ITIMER_REAL, &itv, 0);
/*
* Calculate back from 100 ms to 1 us.
*/
delay_decrement = -i / 100000;
if (verbose >= 2)
fprintf(stderr,
" calibrated to %d cycles per us\n",
delay_decrement);
#endif /* WIN32NATIVE */
}
/*
* Delay for approximately the number of microseconds specified.
* usleep()'s granularity is usually like 1 ms or 10 ms, so it's not
* really suitable for short delays in bit-bang algorithms.
*/
void bitbang_delay(int us)
{
volatile int del = us * delay_decrement;
while (del > 0)
del--;
}
/*
* transmit and receive a byte of data to/from the AVR device
*/
static unsigned char bitbang_txrx(PROGRAMMER * pgm, unsigned char byte)
{
int i;
unsigned char r, b, rbyte;
rbyte = 0;
for (i=7; i>=0; i--) {
/*
* Write and read one bit on SPI.
* Some notes on timing: Let T be the time it takes to do
* one pgm->setpin()-call resp. par clrpin()-call, then
* - SCK is high for 2T
* - SCK is low for 2T
* - MOSI setuptime is 1T
* - MOSI holdtime is 3T
* - SCK low to MISO read is 2T to 3T
* So we are within programming specs (expect for AT90S1200),
* if and only if T>t_CLCL (t_CLCL=clock period of target system).
*
* Due to the delay introduced by "IN" and "OUT"-commands,
* T is greater than 1us (more like 2us) on x86-architectures.
* So programming works safely down to 1MHz target clock.
*/
b = (byte >> i) & 0x01;
/* set the data input line as desired */
pgm->setpin(pgm, pgm->pinno[PIN_AVR_MOSI], b);
pgm->setpin(pgm, pgm->pinno[PIN_AVR_SCK], 1);
/*
* read the result bit (it is either valid from a previous falling
* edge or it is ignored in the current context)
*/
r = pgm->getpin(pgm, pgm->pinno[PIN_AVR_MISO]);
pgm->setpin(pgm, pgm->pinno[PIN_AVR_SCK], 0);
rbyte |= r << i;
}
return rbyte;
}
int bitbang_rdy_led(PROGRAMMER * pgm, int value)
{
pgm->setpin(pgm, pgm->pinno[PIN_LED_RDY], !value);
return 0;
}
int bitbang_err_led(PROGRAMMER * pgm, int value)
{
pgm->setpin(pgm, pgm->pinno[PIN_LED_ERR], !value);
return 0;
}
int bitbang_pgm_led(PROGRAMMER * pgm, int value)
{
pgm->setpin(pgm, pgm->pinno[PIN_LED_PGM], !value);
return 0;
}
int bitbang_vfy_led(PROGRAMMER * pgm, int value)
{
pgm->setpin(pgm, pgm->pinno[PIN_LED_VFY], !value);
return 0;
}
/*
* transmit an AVR device command and return the results; 'cmd' and
* 'res' must point to at least a 4 byte data buffer
*/
int bitbang_cmd(PROGRAMMER * pgm, unsigned char cmd[4],
unsigned char res[4])
{
int i;
for (i=0; i<4; i++) {
res[i] = bitbang_txrx(pgm, cmd[i]);
}
if(verbose >= 2)
{
fprintf(stderr, "bitbang_cmd(): [ ");
for(i = 0; i < 4; i++)
fprintf(stderr, "%02X ", cmd[i]);
fprintf(stderr, "] [ ");
for(i = 0; i < 4; i++)
{
fprintf(stderr, "%02X ", res[i]);
}
fprintf(stderr, "]\n");
}
return 0;
}
/*
* issue the 'chip erase' command to the AVR device
*/
int bitbang_chip_erase(PROGRAMMER * pgm, AVRPART * p)
{
unsigned char cmd[4];
unsigned char res[4];
if (p->op[AVR_OP_CHIP_ERASE] == NULL) {
fprintf(stderr, "chip erase instruction not defined for part \"%s\"\n",
p->desc);
return -1;
}
pgm->pgm_led(pgm, ON);
memset(cmd, 0, sizeof(cmd));
avr_set_bits(p->op[AVR_OP_CHIP_ERASE], cmd);
pgm->cmd(pgm, cmd, res);
usleep(p->chip_erase_delay);
pgm->initialize(pgm, p);
pgm->pgm_led(pgm, OFF);
return 0;
}
/*
* issue the 'program enable' command to the AVR device
*/
int bitbang_program_enable(PROGRAMMER * pgm, AVRPART * p)
{
unsigned char cmd[4];
unsigned char res[4];
if (p->op[AVR_OP_PGM_ENABLE] == NULL) {
fprintf(stderr, "program enable instruction not defined for part \"%s\"\n",
p->desc);
return -1;
}
memset(cmd, 0, sizeof(cmd));
avr_set_bits(p->op[AVR_OP_PGM_ENABLE], cmd);
pgm->cmd(pgm, cmd, res);
if (res[2] != cmd[1])
return -2;
return 0;
}
/*
* initialize the AVR device and prepare it to accept commands
*/
int bitbang_initialize(PROGRAMMER * pgm, AVRPART * p)
{
int rc;
int tries;
bitbang_calibrate_delay();
pgm->powerup(pgm);
usleep(20000);
pgm->setpin(pgm, pgm->pinno[PIN_AVR_SCK], 0);
pgm->setpin(pgm, pgm->pinno[PIN_AVR_RESET], 0);
usleep(20000);
pgm->highpulsepin(pgm, pgm->pinno[PIN_AVR_RESET]);
usleep(20000); /* 20 ms XXX should be a per-chip parameter */
/*
* Enable programming mode. If we are programming an AT90S1200, we
* can only issue the command and hope it worked. If we are using
* one of the other chips, the chip will echo 0x53 when issuing the
* third byte of the command. In this case, try up to 32 times in
* order to possibly get back into sync with the chip if we are out
* of sync.
*/
if (strcmp(p->desc, "AT90S1200")==0) {
pgm->program_enable(pgm, p);
}
else {
tries = 0;
do {
rc = pgm->program_enable(pgm, p);
if ((rc == 0)||(rc == -1))
break;
pgm->highpulsepin(pgm, pgm->pinno[p->retry_pulse/*PIN_AVR_SCK*/]);
tries++;
} while (tries < 65);
/*
* can't sync with the device, maybe it's not attached?
*/
if (rc) {
fprintf(stderr, "%s: AVR device not responding\n", progname);
return -1;
}
}
return 0;
}
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