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antorcha/fw/boot.c

90 lines
1.8 KiB
C

/*
* fw/boot.c - Antorcha boot loader
*
* Written 2012 by Werner Almesberger
* Copyright 2012 Werner Almesberger
*
* 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.
*/
#include <avr/io.h>
#include <avr/pgmspace.h>
#include "io.h"
#include "rf.h"
#include "proto.h"
#include "dispatch.h"
#include "fw.h"
#define MS_TO_LOOP(ms) ((uint32_t) (ms)*106)
static void wait_upload(void)
{
uint8_t buf[PAYLOAD+5]; /* 3 bytes header, 2 bytes CRC */
uint32_t i;
uint8_t got;
restart:
for (i = 0; i != MS_TO_LOOP(5000); i++) {
got = rf_recv(buf, sizeof(buf));
if (got > 2 && fw_packet(buf, got-2))
goto restart;
}
}
int main(void)
{
volatile int zero = 0;
/* Port B has two LEDs and the rest is SPI */
PORTB = MASK(B, RF_nSS) | MASK(B, RF_nRST);
DDRB = MASK(B, RF_SCLK) | MASK(B, RF_MOSI) | MASK(B, RF_nSS) |
MASK(B, RF_nRST) | 0xc0;
/* All port C pins drive LEDs */
PORTC = 0;
DDRC = 0x3f;
/* All port D pins drive LEDs */
PORTD = 0;
DDRD = 0xff;
/* Disable pull-ups */
MCUCR |= 1 << PUD;
/*
* Disable the watchdog timer, in case the boot loader has been
* entered by a watchdog reset commanded by the application.
*/
MCUSR = 0; /* Remove override */
WDTCSR |= 1 << WDCE; /* Enable change */
WDTCSR = 1 << WDCE; /* Disable watchdog while still enabling
change */
rf_init();
/*
* Switch the LED inside the loop so that we get a short pulse one can
* observe on a scope.
*/
do {
SET(LED_B8);
wait_upload();
CLR(LED_B8);
} while (pgm_read_byte(zero) == 0xff);
((void (*)(void)) 0)();
/* not reached */
return 0;
}