protocol/vusb/bootloader_usbasp.c

   1 /*
   2 Copyright 2011 Jun Wako <wakojun@gmail.com>
   3
   4 This program is free software: you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation, either version 2 of the License, or
   7 (at your option) any later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <avr/io.h>
  19 #include <avr/interrupt.h>
  20 #include "bootloader.h"
  21
  22
  23 void bootloader_jump(void) {
  24     cli();
  25     // This makes custom USBasploader come up.
  26     MCUSR = 0;
  27
  28     // ATmega168PA
  29     // initialize ports
  30     PORTB = 0; PORTC= 0; PORTD = 0;
  31     DDRB = 0; DDRC= 0; DDRD = 0;
  32
  33     // disable interrupts
  34     EIMSK = 0; EECR = 0; SPCR = 0;
  35     ACSR = 0; SPMCSR = 0; WDTCSR = 0; PCICR = 0;
  36     TIMSK0 = 0; TIMSK1 = 0; TIMSK2 = 0;
  37     ADCSRA = 0; TWCR = 0; UCSR0B = 0;
  38
  39     // Boot Loader Section Start Address:
  40     // BOOTSZ       Size        Address
  41     // (lock bit)   (word)      (word)      (byte)
  42     // '11'         128         0x1F80      0x3F00
  43     // '10'         256         0x1F00      0x3E00
  44     // '01'         512         0x1E00      0x3C00
  45     // '00'         1024        0x1C00      0x3800
  46     asm volatile("jmp 0x3800");
  47 }