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- // insert cool lengthy disclaimer here
- // snes.c: SNES hardware control (resetting)
- #include <avr/io.h>
- #include "avrcompat.h"
- #include "config.h"
- #include "uart.h"
- #include "snes.h"
- #include "memory.h"
- #include "fileops.h"
- #include "ff.h"
- #include "led.h"
- #include "smc.h"
- uint8_t initloop=1;
- uint32_t saveram_crc, saveram_crc_old;
- uint32_t saveram_base_addr = 0x600000; // chip 3
- void snes_init() {
- DDRD |= _BV(PD5); // PD5 = RESET_DIR
- DDRD |= _BV(PD6); // PD6 = RESET
- snes_reset(1);
- }
- /*
- * sets the SNES reset state.
- *
- * state: put SNES in reset state when 1, release when 0
- */
- void snes_reset(int state) {
- if(state) {
- DDRD |= _BV(PD6); // /RESET pin -> out
- PORTD &= ~_BV(PD6); // /RESET = 0
- PORTD |= _BV(PD5); // RESET_DIR = 1;
- } else {
- PORTD &= ~_BV(PD5); // RESET_DIR = 0;
- DDRD &= ~_BV(PD6); // /RESET pin -> in
- PORTD |= _BV(PD6); // /RESET = pullup
- }
- }
- /*
- * gets the SNES reset state.
- *
- * returns: 1 when reset, 0 when not reset
- */
- uint8_t get_snes_reset() {
- // DDRD &= ~_BV(PD6); // /RESET pin -> in
- // PORTD &= ~_BV(PD5); // RESET_DIR (external buffer) = 0
- return !(PIND & _BV(PD6));
- }
- /*
- * SD2SNES main loop.
- * monitors SRAM changes and other things
- */
- uint32_t diffcount = 0, samecount = 0, didnotsave = 0;
- uint8_t sram_valid = 0;
- void snes_main_loop() {
- if(!romprops.ramsize_bytes)return;
- if(initloop) {
- saveram_crc_old = calc_sram_crc(saveram_base_addr, romprops.ramsize_bytes);
- initloop=0;
- }
- saveram_crc = calc_sram_crc(saveram_base_addr, romprops.ramsize_bytes);
- sram_valid = sram_reliable();
- if(crc_valid && sram_valid) {
- if(saveram_crc != saveram_crc_old) {
- if(samecount) {
- diffcount=1;
- } else {
- diffcount++;
- didnotsave++;
- }
- samecount=0;
- }
- if(saveram_crc == saveram_crc_old) {
- samecount++;
- }
- if(diffcount>=1 && samecount==5) {
- uart_putc('U');
- uart_puthexshort(saveram_crc);
- uart_putcrlf();
- set_busy_led(1);
- save_sram(file_lfn, romprops.ramsize_bytes, saveram_base_addr);
- set_busy_led(0);
- didnotsave=0;
- }
- if(didnotsave>50) {
- diffcount=0;
- uart_putc('V');
- set_busy_led(1);
- save_sram(file_lfn, romprops.ramsize_bytes, saveram_base_addr);
- didnotsave=0;
- set_busy_led(0);
- }
- saveram_crc_old = saveram_crc;
- }
- dprintf("crc_valid=%d sram_valid=%d diffcount=%ld samecount=%ld, didnotsave=%ld\n", crc_valid, sram_valid, diffcount, samecount, didnotsave);
- }
- /*
- * SD2SNES menu loop.
- * monitors menu selection. return when selection was made.
- */
- uint8_t menu_main_loop() {
- uint8_t cmd = 0;
- sram_writebyte(0, SRAM_CMD_ADDR);
- while(!cmd) {
- if(!get_snes_reset()) {
- while(!sram_reliable());
- cmd = sram_readbyte(SRAM_CMD_ADDR);
- }
- if(get_snes_reset()) {
- cmd = 0;
- }
- }
- return cmd;
- }
- void get_selected_name(uint8_t* fn) {
- uint32_t addr = sram_readlong(SRAM_FD_ADDR);
- dprintf("fd addr=%lX\n", addr);
- sram_readblock(fn, addr+0x41, 256);
- }
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