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BQ78350-R1A: Unable to write data to registers from SMBUS pin through CP2112 USB-SMBUS tool.

Part Number: BQ78350-R1A
Other Parts Discussed in Thread: BQSTUDIO

We are using the CP2112 USB-SMBUS Bridge to read and write data to the BQ78350-R1A. While we have been successful in reading data through the CP2112, however we are unable to write any data to the registers. We are using C for performing the operations. 

The format for writing data as per the CP2112 documentation is as below:

HID_SMBUS_STATUS HidSmbus_WriteRequest (HID_SMBUS_DEVICE device, BYTE slaveAddress, BYTE* buffer, BYTE numBytesToWrite)

Considering we want to toggle the LED using the manufacturer access, 0x002B is to be written to the manufacturer access 0x00. We have written the code as,

BYTE* buffer[] = {0x00,0x2b00};

SMBus_Write(HIDDEVICE, buffer, slave_address, 3);

However, this seems to be the wrong format/syntax as we arent getting the outcome.

Would appreciate if someone can show the right syntax for writing data to the registers. Thank You.

  • Hello Mainak,

    I would check LSB, MSB first.

    If that does not work, then try the same transactions through bqStudio Advanced Comm Tab to get a better understanding.

    For third party SMBus bridge, it is best to contact the manufacturer for support. It should be easy to fix if something works in bqStudio and does not work with the bridge.