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The main function I'm having a problem with is where I'm writing a value to external EEPROM. I clear the EEPROM, then write my value to it, waiting 100ms afterwards.

#define BAUD_RATE (int)100e3 // the standard baud rate
...
void initIR(){
    bcm2835_init();
    bcm2835_i2c_begin();
    bcm2835_i2c_set_baudrate((int)BAUD_RATE);
    bcm2835_i2c_setSlaveAddress(0x5a);
}
void writeConfig(){
    unsigned char comm = 0x25; // the command to send. access EEPROM
    unsigned char * write = (unsigned char *)malloc(sizeof(unsigned char) * 9); 
    unsigned char * clear = (unsigned char *)malloc(sizeof(unsigned char) * 9);

    write[0] = 0x25; write[1] = 0x74; write[2] = 0xb4; write[3] = 0x70;
    clear[0] = 0x25; clear[1] = 0x00; clear[2] = 0x00; clear[3] = 0x83;

    /*bcm2835_i2c_begin();*/
    int c = bcm2835_i2c_write(clear, 3);
    waitMillis(100);
    int w = bcm2835_i2c_write(write, 3);
    waitMillis(100);


    printf("c: %d, w: %d\n", c, w);
    free(clear);
    free(write);
}

Other I2C functions work, so I know my baud rate and slave address are correct. The function bcm2835_i2c_write returns...

| Return value | Message                        |
|:------------:|:------------------------------:|
| 0            | Message received OK            |
| 1            | Received NACK                  |
| 2            | Received clock stretch timeout |
| 3            | Not all data sent/received     |

When I don't include the PEC, I receive a 0, but the value in EEPROM doesn't change (and as expected). When I include the PEC, I receive a 1, and the value in EEPROM doesn't change.

How do I fix write to EEPROM?

1 Answer 1

1

Turns out turning the device off then on after writing to the EEPROM will fix this error. Apparently the EEPROM is only loaded on startup (at least for this device).

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