3. Flash a .hex file
4. Reset the device into application mode (may be done automatically)
+## USBasploader
+
+USBasploader is a bootloader developed by matrixstorm. It is used in some non-USB AVR chips such as the ATmega328P, which run V-USB.
+
+To ensure compatibility with the USBasploader bootloader, make sure this block is present in your `rules.mk`:
+
+ # Bootloader
+ # This definition is optional, and if your keyboard supports multiple bootloaders of
+ # different sizes, comment this out, and the correct address will be loaded
+ # automatically (+60). See bootloader.mk for all options.
+ BOOTLOADER = USBasp
+
+Compatible flashers:
+
+* [QMK Toolbox](https://github.com/qmk/qmk_toolbox/releases) (recommended GUI)
+* [avrdude](http://www.nongnu.org/avrdude/) with the `usbasp` programmer
+* [AVRDUDESS](https://github.com/zkemble/AVRDUDESS)
+
+Flashing sequence:
+
+1. Press the `RESET` keycode, or keep the boot pin shorted to GND while quickly shorting RST to GND
+2. Wait for the OS to detect the device
+3. Flash a .hex file
+4. Reset the device into application mode (may be done automatically)
+
## STM32
All STM32 chips come preloaded with a factory bootloader that cannot be modified nor deleted. Some STM32 chips have bootloaders that do not come with USB programming (e.g. STM32F103) but the process is still the same.
#define BOOT_SIZE_1024 0b010
#define BOOT_SIZE_2048 0b000
+//compatibility between ATMega8 and ATMega88
+#if !defined (MCUCSR)
+ #if defined (MCUSR)
+ #define MCUCSR MCUSR
+ #endif
+#endif
+
/** \brief Entering the Bootloader via Software
*
* http://www.fourwalledcubicle.com/files/LUFA/Doc/120730/html/_page__software_bootloader_start.html
while(1) {} // wait for watchdog timer to trigger
+ #elif defined(BOOTLOADER_USBASP)
+ // Taken with permission of Stephan Baerwolf from https://github.com/tinyusbboard/API/blob/master/apipage.c
+ wdt_enable(WDTO_15MS);
+ wdt_reset();
+ asm volatile (
+ "cli \n\t"
+ "ldi r29 , %[ramendhi] \n\t"
+ "ldi r28 , %[ramendlo] \n\t"
+ #if (FLASHEND>131071)
+ "ldi r18 , %[bootaddrhi] \n\t"
+ "st Y+, r18 \n\t"
+ #endif
+ "ldi r18 , %[bootaddrme] \n\t"
+ "st Y+, r18 \n\t"
+ "ldi r18 , %[bootaddrlo] \n\t"
+ "st Y+, r18 \n\t"
+ "out %[mcucsrio], __zero_reg__ \n\t"
+ "bootloader_startup_loop%=: \n\t"
+ "rjmp bootloader_startup_loop%= \n\t"
+ :
+ : [mcucsrio] "I" (_SFR_IO_ADDR(MCUCSR)),
+ #if (FLASHEND>131071)
+ [ramendhi] "M" (((RAMEND - 2) >> 8) & 0xff),
+ [ramendlo] "M" (((RAMEND - 2) >> 0) & 0xff),
+ [bootaddrhi] "M" ((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >>16) & 0xff),
+ #else
+ [ramendhi] "M" (((RAMEND - 1) >> 8) & 0xff),
+ [ramendlo] "M" (((RAMEND - 1) >> 0) & 0xff),
+ #endif
+ [bootaddrme] "M" ((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff),
+ [bootaddrlo] "M" ((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff)
+ );
+
#else // Assume remaining boards are DFU, even if the flag isn't set
#if !(defined(__AVR_ATmega32A__) || defined(__AVR_ATmega328P__)) // no USB - maybe BOOTLOADER_BOOTLOADHID instead though?
}
-#ifdef __AVR_ATmega32A__
- // MCUSR is actually called MCUCSR in ATmega32A
- #define MCUSR MCUCSR
-#endif
-
/* this runs before main() */
void bootloader_jump_after_watchdog_reset(void) __attribute__ ((used, naked, section (".init3")));
void bootloader_jump_after_watchdog_reset(void)
{
#ifndef BOOTLOADER_HALFKAY
- if ((MCUSR & (1<<WDRF)) && reset_key == BOOTLOADER_RESET_KEY) {
+ if ((MCUCSR & (1<<WDRF)) && reset_key == BOOTLOADER_RESET_KEY) {
reset_key = 0;
// My custom USBasploader requires this to come up.
- MCUSR = 0;
+ MCUCSR = 0;
// Seems like Teensy halfkay loader requires clearing WDRF and disabling watchdog.
- MCUSR &= ~(1<<WDRF);
+ MCUCSR &= ~(1<<WDRF);
wdt_disable();
}
#endif
}
-
-
-#if 0
- /*
- * USBaspLoader - I'm not sure if this is used at all in any projects
- * would love to support it if it is -Jack
- */
-#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega168P__) || defined(__AVR_ATmega328P__)
- // This makes custom USBasploader come up.
- MCUSR = 0;
-
- // initialize ports
- PORTB = 0; PORTC= 0; PORTD = 0;
- DDRB = 0; DDRC= 0; DDRD = 0;
-
- // disable interrupts
- EIMSK = 0; EECR = 0; SPCR = 0;
- ACSR = 0; SPMCSR = 0; WDTCSR = 0; PCICR = 0;
- TIMSK0 = 0; TIMSK1 = 0; TIMSK2 = 0;
- ADCSRA = 0; TWCR = 0; UCSR0B = 0;
-#endif
-
- // This is compled into 'icall', address should be in word unit, not byte.
- ((void (*)(void))(BOOTLOADER_START/2))();
-}
-#endif