chemion_encode.c

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>

uint8_t checksum(uint8_t *in) {
    uint8_t crc = 0x07;                // CRC Magic Number

    int i;
    for (i = 7; i <= 61; i ++) {       // CRC for 54Byte LED Matrix
        crc = crc ^ in[i] & 0xff;      // Each Byte is XORed ontop of the last
    }

    return crc;
}


int main() {

    uint8_t msg[64] = {0xFA, 0x03, 0x00, 0x39, 0x01, 0x00, 0x06,  // Starting Bytes
                       0xC0, 0X00, 0X00, 0X00, 0X00, 0X00,        // LED Matrix
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00,
                       0x00, 0X00, 0X00, 0X00, 0X00, 0X00};

    msg[62] = checksum(msg);    // Get CRC
    msg[63] = 0x55;             // Ending Bytes
    msg[64] = 0xa9;             // Ending Bytes

    // Check values
    int i;
    for(i = 0; i <= 64; i++) {
        printf("Msg %i: %i\n", i, msg[i]);
    } 

}