collapseos/emul/hw/rc2014/sdc.h
Virgil Dupras 1a6a549857 Make the SPI Relay protocol support multiple devices
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.
2020-09-17 09:48:55 -04:00

37 lines
1.2 KiB
C

#include <stdint.h>
#include <stdbool.h>
typedef struct {
bool selected;
// Initialization status. 0 == not woken 8 == woken 9 == CMD0 received
// 10 == CMD8 received, 11 == CMD55 received, 12 == CMD41 received (fully
// initialized).
unsigned int initstat;
// We receive commands into this buffer.
uint8_t recvbuf[6];
// Where the next SPI byte should be stored in recvbuf.
unsigned int recvidx;
// Buffer to the arguments for a response
uint8_t sendbuf[5];
// Index of the next byte from sendbuf we should return. If -1, buffer is
// empty.
int sendidx;
// One byte response. When all other response buffers are empty, return
// this.
uint8_t resp;
// File used for contents read/write
FILE *fp;
// number of bytes read into the current CMD17. -1 means no CMD17 active.
int cmd17bytes;
// number of bytes received for the current CMD24. -2 means no CMD24 active.
// -1 means we're still waiting for the data token.
int cmd24bytes;
// running crc16 during read and write operations.
uint16_t crc16;
} SDC;
void sdc_init(SDC *sdc);
void sdc_ctl_wr(SDC *sdc, uint8_t val);
void sdc_spi_wr(SDC *sdc, uint8_t val);
uint8_t sdc_spi_rd(SDC *sdc);