mirror of
https://github.com/openhwgroup/cvw
synced 2025-01-23 21:14:37 +00:00
32 lines
614 B
C
32 lines
614 B
C
#include "sd.h"
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#include "spi.h"
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uint8_t crc7(uint8_t prev, uint8_t in) {
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// CRC polynomial 0x89
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uint8_t remainder = prev & in;
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remainder ^= (remainder >> 4) ^ (remainder >> 7);
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remainder ^= remainder << 4;
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return remainder & 0x7f;
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}
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uint16_t crc16(uint16_t crc, uint8_t data) {
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// CRC polynomial 0x11021
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crc = (uint8_t)(crc >> 8) | (crc << 8);
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crc ^= data;
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crc ^= (uint8_t)(crc >> 4) & 0xf;
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crc ^= crc << 12;
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crc ^= (crc & 0xff) << 5;
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return crc;
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}
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uint8_t sd_cmd(uint8_t cmd, uint32_t arg, uint8_t crc) {
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spi_send_byte
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}
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void init_sd(){
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init_spi();
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}
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