sd2snes/src/cic.c

75 lines
1.8 KiB
C

#include <arm/NXP/LPC17xx/LPC17xx.h>
#include "bits.h"
#include "config.h"
#include "uart.h"
#include "cic.h"
char *cicstatenames[3] = { "CIC_OK", "CIC_FAIL", "CIC_PAIR" };
void print_cic_state() {
printf("CIC state: %s\n", get_cic_statename(get_cic_state()));
}
inline char *get_cic_statename(enum cicstates state) {
return cicstatenames[state];
}
enum cicstates get_cic_state() {
uint32_t count;
uint32_t togglecount = 0;
uint8_t state, state_old;
state_old = BITBAND(SNES_CIC_STATUS_REG->FIOPIN, SNES_CIC_STATUS_BIT);
/* this loop samples at ~10MHz */
for(count=0; count<1000; count++) {
state = BITBAND(SNES_CIC_STATUS_REG->FIOPIN, SNES_CIC_STATUS_BIT);
if(state != state_old) {
togglecount++;
}
state_old = state;
}
if(togglecount > 20) {
printf("%ld\n", togglecount);
return CIC_PAIR;
}
if(state) {
return CIC_OK;
}
return CIC_FAIL;
}
void cic_init(int allow_pairmode) {
BITBAND(SNES_CIC_PAIR_REG->FIODIR, SNES_CIC_PAIR_BIT) = 1;
if(allow_pairmode) {
BITBAND(SNES_CIC_PAIR_REG->FIOCLR, SNES_CIC_PAIR_BIT) = 1;
} else {
BITBAND(SNES_CIC_PAIR_REG->FIOSET, SNES_CIC_PAIR_BIT) = 1;
}
}
/* prepare GPIOs for pair mode + set initial modes */
void cic_pair(int init_vmode, int init_d4) {
cic_videomode(init_vmode);
cic_d4(init_d4);
BITBAND(SNES_CIC_D0_REG->FIODIR, SNES_CIC_D0_BIT) = 1;
BITBAND(SNES_CIC_D1_REG->FIODIR, SNES_CIC_D1_BIT) = 1;
}
void cic_videomode(int value) {
if(value) {
BITBAND(SNES_CIC_D0_REG->FIOSET, SNES_CIC_D0_BIT) = 1;
} else {
BITBAND(SNES_CIC_D0_REG->FIOCLR, SNES_CIC_D0_BIT) = 1;
}
}
void cic_d4(int value) {
if(value) {
BITBAND(SNES_CIC_D1_REG->FIOSET, SNES_CIC_D1_BIT) = 1;
} else {
BITBAND(SNES_CIC_D1_REG->FIOCLR, SNES_CIC_D1_BIT) = 1;
}
}