60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/* Copyright 2021 QMK
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "bootloader.h"
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#include <avr/wdt.h>
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#include <util/delay.h>
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#define FLASH_SIZE (FLASHEND + 1L)
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/** \brief Entering the Bootloader via Software
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*
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* http://www.fourwalledcubicle.com/files/LUFA/Doc/120730/html/_page__software_bootloader_start.html
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*/
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#define BOOTLOADER_RESET_KEY 0xB007B007
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uint32_t reset_key __attribute__((section(".noinit,\"aw\",@nobits;")));
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__attribute__((weak)) void bootloader_jump(void) {
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UDCON = 1;
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USBCON = (1 << FRZCLK); // disable USB
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UCSR1B = 0;
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_delay_ms(5); // 5 seems to work fine
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reset_key = BOOTLOADER_RESET_KEY;
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// watchdog reset
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wdt_enable(WDTO_250MS);
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for (;;)
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;
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}
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__attribute__((weak)) void mcu_reset(void) {
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// watchdog reset
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wdt_enable(WDTO_250MS);
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for (;;)
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;
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}
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/* this runs before main() */
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void bootloader_jump_after_watchdog_reset(void) __attribute__((used, naked, section(".init3")));
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void bootloader_jump_after_watchdog_reset(void) {
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if ((MCUSR & (1 << WDRF)) && reset_key == BOOTLOADER_RESET_KEY) {
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reset_key = 0;
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((void (*)(void))((FLASH_SIZE - BOOTLOADER_SIZE) >> 1))();
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}
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}
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