147 lines
3.8 KiB
C
147 lines
3.8 KiB
C
/* sd2snes - SD card based universal cartridge for the SNES
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Copyright (C) 2009-2010 Maximilian Rehkopf <otakon@gmx.net>
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AVR firmware portion
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Inspired by and based on code from sd2iec, written by Ingo Korb et al.
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See sdcard.c|h, config.h.
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FAT file system access based on code by ChaN, Jim Brain, Ingo Korb,
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see ff.c|h.
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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; version 2 of the License only.
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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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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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snes.c: SNES hardware control and monitoring
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*/
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#include <avr/io.h>
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#include "avrcompat.h"
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#include "config.h"
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#include "uart.h"
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#include "snes.h"
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#include "memory.h"
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#include "fileops.h"
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#include "ff.h"
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#include "led.h"
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#include "smc.h"
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uint8_t initloop=1;
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uint32_t saveram_crc, saveram_crc_old;
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void snes_init() {
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DDRD |= _BV(PD5); // PD5 = RESET_DIR
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DDRD |= _BV(PD6); // PD6 = RESET
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snes_reset(1);
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}
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/*
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* sets the SNES reset state.
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*
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* state: put SNES in reset state when 1, release when 0
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*/
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void snes_reset(int state) {
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if(state) {
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DDRD |= _BV(PD6); // /RESET pin -> out
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PORTD &= ~_BV(PD6); // /RESET = 0
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PORTD |= _BV(PD5); // RESET_DIR = 1;
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} else {
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PORTD &= ~_BV(PD5); // RESET_DIR = 0;
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DDRD &= ~_BV(PD6); // /RESET pin -> in
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PORTD |= _BV(PD6); // /RESET = pullup
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}
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}
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/*
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* gets the SNES reset state.
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*
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* returns: 1 when reset, 0 when not reset
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*/
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uint8_t get_snes_reset() {
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// DDRD &= ~_BV(PD6); // /RESET pin -> in
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// PORTD &= ~_BV(PD5); // RESET_DIR (external buffer) = 0
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return !(PIND & _BV(PD6));
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}
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/*
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* SD2SNES main loop.
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* monitors SRAM changes and other things
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*/
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uint32_t diffcount = 0, samecount = 0, didnotsave = 0;
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uint8_t sram_valid = 0;
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void snes_main_loop() {
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if(!romprops.ramsize_bytes)return;
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if(initloop) {
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saveram_crc_old = calc_sram_crc(SRAM_SAVE_ADDR, romprops.ramsize_bytes);
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initloop=0;
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}
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saveram_crc = calc_sram_crc(SRAM_SAVE_ADDR, romprops.ramsize_bytes);
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sram_valid = sram_reliable();
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if(crc_valid && sram_valid) {
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if(saveram_crc != saveram_crc_old) {
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if(samecount) {
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diffcount=1;
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} else {
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diffcount++;
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didnotsave++;
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}
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samecount=0;
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}
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if(saveram_crc == saveram_crc_old) {
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samecount++;
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}
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if(diffcount>=1 && samecount==5) {
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uart_putc('U');
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uart_puthexshort(saveram_crc);
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uart_putcrlf();
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set_busy_led(1);
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save_sram(file_lfn, romprops.ramsize_bytes, SRAM_SAVE_ADDR);
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set_busy_led(0);
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didnotsave=0;
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}
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if(didnotsave>50) {
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diffcount=0;
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uart_putc('V');
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set_busy_led(1);
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save_sram(file_lfn, romprops.ramsize_bytes, SRAM_SAVE_ADDR);
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didnotsave=0;
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set_busy_led(0);
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}
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saveram_crc_old = saveram_crc;
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}
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dprintf("crc_valid=%d sram_valid=%d diffcount=%ld samecount=%ld, didnotsave=%ld\n", crc_valid, sram_valid, diffcount, samecount, didnotsave);
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}
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/*
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* SD2SNES menu loop.
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* monitors menu selection. return when selection was made.
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*/
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uint8_t menu_main_loop() {
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uint8_t cmd = 0;
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sram_writebyte(0, SRAM_CMD_ADDR);
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while(!cmd) {
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if(!get_snes_reset()) {
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while(!sram_reliable());
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cmd = sram_readbyte(SRAM_CMD_ADDR);
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}
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if(get_snes_reset()) {
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cmd = 0;
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}
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}
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return cmd;
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}
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void get_selected_name(uint8_t* fn) {
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uint32_t addr = sram_readlong(SRAM_FD_ADDR);
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dprintf("fd addr=%lX\n", addr);
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sram_readblock(fn, addr+0x41+SRAM_MENU_ADDR, 256);
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}
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