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core: Add bootkey of Caterina bootloader

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The bootkey set in bootloader_jump() works with Pro Micro and Leonardo.
This fix doesn't seem to prevent other bootloaders, however, it can be
disabled by defining NO_BOOTLOADER_CATERINA_BOOTKEY.
This commit is contained in:
tmk 2019-09-16 17:49:38 +09:00
parent f5e487bc38
commit 19350e3ee5
1 changed files with 15 additions and 0 deletions
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15
tmk_core/common/avr/bootloader.c
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@ -87,6 +87,14 @@ void bootloader_jump(void) {
_delay_ms(5);
#endif
#ifndef NO_BOOTLOADER_CATERINA_BOOTKEY
// Set bootkey for Arduino Leonardo and Pro Micro bootloader
// Watchdog reset with bootkey causes the bootloader to enter program mode instead of starting application.
// https://github.com/arduino/ArduinoCore-avr/blob/master/bootloaders/caterina/Caterina.c#L68-L69
// https://github.com/sparkfun/SF32u4_boards/blob/master/sparkfun/avr/bootloaders/caterina/Caterina.c#L88-L89
*(volatile uint16_t *)0x0800 = 0x7777;
#endif
// watchdog reset
reset_key = BOOTLOADER_RESET_KEY;
wdt_enable(WDTO_250MS);
@ -108,6 +116,13 @@ void bootloader_jump_after_watchdog_reset(void)
MCUSR &= ~(1<<WDRF);
wdt_disable();
#ifndef NO_BOOTLOADER_CATERINA_BOOTKEY
// Clear bootkey of Caterina bootloader for other bootloaders
// Leonardo and Pro Micro with Arduino default fuse setting don't reach here
// because bootloader section are executed before application everytime.
*(volatile uint16_t *)0x0800 = 0;
#endif
// This is compled into 'icall', address should be in word unit, not byte.
((void (*)(void))(BOOTLOADER_START/2))();
}