10 bits (value encoded in 8 high bit + 2 low bit) into decimal ?

Hello Julien,

An aside before I answer this - you would most likely find 8-bit data sufficient, and it will make everything a bit easier. 8-Channels at 10-bits is pushing the limits of the Bluetooth bandwidth and the sensors processors.

You are close! You are correct in most of your surmises so far. You expect 11 bytes, with the first byte being a signature.

1. Signature (75 = 8channels, 10-bit)
2. Chan 1 MSB
3. Chan 2 MSB
...
8. Chan 7 MSB
9. Chan 8 MSB
10. Overflow LSB 11223344
11. Overflow LSB 55667788

The relevant code is in flexvolt.js . You can see where I store the two overflow bytes, then for each channel, shift the MSB left by 2 and append relevant 2 bits from overflow.

var readInd = 0, dataInd = 0;
while(readInd < (dataIn.length-api.readParams.expectedBytes) ){
    var tmp = dataIn[readInd++];
    if (tmp === api.readParams.expectedChar){
        dataTimes.push(timestamp); 
        timestamp+=timestampInterval*hardwareLogic.settings.downSampleCount;
        if (!hardwareLogic.settings.bitDepth10) {
            for (iChan = 0; iChan < hardwareLogic.settings.nChannels; iChan++){
                dataParsed[iChan][dataInd] = factor8Bit*(dataIn[readInd++] - api.readParams.offset); // centering on 0!
            }
            dataInd++;
        } else if (hardwareLogic.settings.bitDepth10) {
            tmpLow = dataIn[readInd+hardwareLogic.settings.nChannels];
            if (hardwareLogic.settings.nChannels > 4) {
              tmpLow2 = dataIn[readInd+hardwareLogic.settings.nChannels+1];
            }
            for (iChan = 0; iChan < Math.min(4, hardwareLogic.settings.nChannels); iChan++){
                dataParsed[iChan][dataInd] = factor10Bit*((dataIn[readInd++]<<2) + ((tmpLow>>(2*(3-iChan))) & 3) - api.readParams.offset); // centering on 0!
            }
            for (iChan = 4; iChan < hardwareLogic.settings.nChannels; iChan++){
                dataParsed[iChan][dataInd] = factor10Bit*((dataIn[readInd++]<<2) + ((tmpLow2>>(2*(3-iChan))) & 3) - api.readParams.offset); // centering on 0!
            }
            readInd++; // for the tmpLow read
            if (hardwareLogic.settings.nChannels > 4) {
              readInd++; // for the tmpLow2 read
            }
            dataInd++;
        }

    } else if (tmp === 116) { //'t' - voltage statement
        var batteryVoltage = dataIn[readInd++];
        console.log('INFO: Got Battery Level: ' + JSON.stringify(batteryVoltage));
        updateBatteryVoltage(batteryVoltage);
        break; // kick back out -
    } else {
        console.log('WARNING: unexpected Char '+tmp);
    }
}