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97a46a7b9b
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.
18 lines
402 B
C
18 lines
402 B
C
#include "emul.h"
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/* Emulates a SPI relay designed for the RC2014, enabled by poking on the CTL
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port, then allowing a SPI exchange by writing to, then reading from, the
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data port.
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*/
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typedef struct {
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bool selected;
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byte resp;
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EXCH spixfn;
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} SPI;
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void spi_init(SPI *spi, EXCH spixfn);
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void spi_ctl_wr(SPI *spi, byte val);
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void spi_wr(SPI *spi, byte val);
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byte spi_rd(SPI *spi);
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