Checksum testing - Githubissues

Hello, I found your wonderful library on github.

I looked at your checksum code and tried to adapt it for my code. This is what I came up with:

uint16_t mcp3x5xChecksum(const uint8_t* data, size_t length) {
    assert(data);

    const uint16_t initialValue = 0x0000;

    uint16_t crc = initialValue;
    for (size_t index=0; index < length; ++index) {
        crc = spi_mcp3x6x_AddCRC(crc, data[index]);
    }
    return crc;
}

Then I fed in some data from my converter. and ran a small test

    // (status, adcHigh, adcMiddle, adcLow, crcHigh, crcLow } 
    const uint8_t readAdcBytes[] = {0x13, 0xd4, 0xef, 0xff, 0x10, 0xfe};
    const size_t crcSize = sizeof(uint16_t);
    const size_t payloadSize = sizeof(readAdcBytes) - crcSize;
    const uint16_t payloadCrc = mcp3x5xChecksum(readAdcBytes, payloadSize);

    PRINTF("%s ", __func__);
    print_hex(readAdcBytes, payloadSize);
    PRINTF(" crc16=0x%04" PRIx16, payloadCrc);
    PRINTF(" versus 0x%02x %02x" NEWLINE, readAdcBytes[4], readAdcBytes[5]);

This is the output I got: testMcp3x5xChecksum 13 d4 ef ff crc16=0x1218 versus 0x10 fe

Obviously 0x128 does not math 0x10fe

Note that I have enabled CRCCOM and my format is 16 bit (default)

I would have emailed the question directly but the only way to reach out to you (that I know about) is through github issues.

Questions: Did you test the CRCCOM functionality? I did not find that in your examples.

obbo-pl / mcp3x6x-c-lib

Checksum testing #2