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Working on programming AVR chips exposes a glaring omission in my first design of the SPI Relay: not allowing multiple devices make this task hard. I constantly have to unplug my SD card before, plug the AVR chip holder, then play a bit, then unplug the AVR holder, then replug the SD card... My prototype for a SPI relay design is built, but I haven't tested it yet. I need to adapt the code first, which is what I do here. When the prototype is tested, I'll update the SDC recipe with a new schema.
37 lines
1.2 KiB
C
37 lines
1.2 KiB
C
#include <stdint.h>
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#include <stdbool.h>
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typedef struct {
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bool selected;
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// Initialization status. 0 == not woken 8 == woken 9 == CMD0 received
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// 10 == CMD8 received, 11 == CMD55 received, 12 == CMD41 received (fully
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// initialized).
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unsigned int initstat;
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// We receive commands into this buffer.
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uint8_t recvbuf[6];
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// Where the next SPI byte should be stored in recvbuf.
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unsigned int recvidx;
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// Buffer to the arguments for a response
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uint8_t sendbuf[5];
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// Index of the next byte from sendbuf we should return. If -1, buffer is
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// empty.
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int sendidx;
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// One byte response. When all other response buffers are empty, return
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// this.
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uint8_t resp;
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// File used for contents read/write
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FILE *fp;
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// number of bytes read into the current CMD17. -1 means no CMD17 active.
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int cmd17bytes;
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// number of bytes received for the current CMD24. -2 means no CMD24 active.
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// -1 means we're still waiting for the data token.
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int cmd24bytes;
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// running crc16 during read and write operations.
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uint16_t crc16;
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} SDC;
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void sdc_init(SDC *sdc);
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void sdc_ctl_wr(SDC *sdc, uint8_t val);
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void sdc_spi_wr(SDC *sdc, uint8_t val);
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uint8_t sdc_spi_rd(SDC *sdc);
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