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collapseos/emul/z80/rc2014_spi.h
Virgil Dupras 97a46a7b9b emul/z80: decouple SDC and SPI
My idea of plugging a RC2014 bridge directly onto a Sega Master System
cartridge doesn't work. The SMS eats all I/O addr space, we can't use
it. Therefore, this naive idea, in the emulator, of reusing sdc.c in
sms.c as-is, doesn't work either.

I'll have to find another way of communicating to a SPI device on the
SMS. I'll probably do it through a controller port. Meanwhile, I need
to decouple SPI from SDC in the emulator code so that I can reuse
sdc.c. This is what is done here.
2020-10-29 15:01:25 -04:00

18 lines
402 B
C

#include "emul.h"
/* Emulates a SPI relay designed for the RC2014, enabled by poking on the CTL
port, then allowing a SPI exchange by writing to, then reading from, the
data port.
*/
typedef struct {
bool selected;
byte resp;
EXCH spixfn;
} SPI;
void spi_init(SPI *spi, EXCH spixfn);
void spi_ctl_wr(SPI *spi, byte val);
void spi_wr(SPI *spi, byte val);
byte spi_rd(SPI *spi);