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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.
29 lines
517 B
C
29 lines
517 B
C
#include "rc2014_spi.h"
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void spi_init(SPI *spi, EXCH spixfn)
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{
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spi->selected = false;
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spi->resp = 0xff;
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spi->spixfn = spixfn;
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}
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// TODO: for now, any nonzero value enables the SPI. To allow
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// emulation of systems with multi-devices SPI relay, change
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// this.
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void spi_ctl_wr(SPI *spi, byte val)
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{
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spi->selected = val;
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}
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void spi_wr(SPI *spi, byte val)
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{
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if (spi->selected) {
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spi->resp = spi->spixfn(val);
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}
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}
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byte spi_rd(SPI *spi)
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{
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return spi->selected ? spi->resp : 0xff;
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}
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