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Although the SPI Relay driver is RC2014-specific, the SD Card driver is generic enough to be a subsystem. That's the second subsystem we add and this warrants, I think, the formalization of a new concept: protocols.
17 lines
586 B
Plaintext
17 lines
586 B
Plaintext
( cmd arg1 arg2 -- resp )
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( Sends a command to the SD card, along with arguments and
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specified CRC fields. (CRC is only needed in initial commands
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though). This does *not* handle CS. You have to
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select/deselect the card outside this routine. )
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: _cmd
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_wait DROP ROT ( a1 a2 cmd )
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0 _s+crc ( a1 a2 crc )
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ROT 256 /MOD ROT ( a2 h l crc )
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_s+crc _s+crc ( a2 crc )
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SWAP 256 /MOD ROT ( h l crc )
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_s+crc _s+crc ( crc )
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0x01 OR ( ensure stop bit )
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(spix) DROP ( send CRC )
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_wait ( wait for a valid response... )
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;
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