nes-proj/cpu/avr/bootloader.c
2010-11-03 16:55:40 +00:00

62 lines
1.2 KiB
C

#include "bootloader.h"
#include "dev/watchdog.h"
#include <util/delay.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "dev/usb/usb_drv.h"
volatile uint32_t Boot_Key ATTR_NO_INIT;
bool
bootloader_is_present(void) {
return pgm_read_word_far(BOOTLOADER_START_ADDRESS)!=0xFFFF;
}
void
Jump_To_Bootloader(void)
{
uint8_t i;
#ifdef UDCON
// If USB is used, detach from the bus
Usb_detach();
#endif
// Disable all interrupts
cli();
// Set the bootloader key to the magic value and force a reset
Boot_Key = MAGIC_BOOT_KEY;
// Wait two seconds for the USB detachment to register on the host
for (i = 0; i < 128; i++)
_delay_ms(16);
// Set the bootloader key to the magic value and force a reset
Boot_Key = MAGIC_BOOT_KEY;
watchdog_reboot();
}
extern void Bootloader_Jump_Check(void) ATTR_INIT_SECTION(3);
void
Bootloader_Jump_Check(void)
{
// If the reset source was the bootloader and the key is correct, clear it and jump to the bootloader
if(MCUSR & (1<<WDRF)) {
MCUSR = 0;
if(Boot_Key == MAGIC_BOOT_KEY) {
Boot_Key = 0;
wdt_disable();
((void (*)(void))BOOTLOADER_START_ADDRESS)();
} else {
Boot_Key++;
}
} else {
Boot_Key = MAGIC_BOOT_KEY-4;
}
}