MCP3201 setup notes

Now I have assembled a voltage divider to divided the input analogue voltage by half, so that input greater than the reference voltage 4.10V will not be over ranged.  So 5V will be divided to become 2.5V etc.

I need to double the calculated value in the final step, as listed below.



    spiGuzuntyPi = spidev.SpiDev()
    spiGuzuntyPi.open(0, 0)

    DummyDoubleByteList = [0x00, 0x00]
    adcOutputDoubleByteList = [0x55, 0x55]
    adcOutputDoubleByteList = spiGuzuntyPi.xfer2(DummyDoubleByteList)

    PrintEightBitPattern("ADC output byte 1 = ", adcOutputDoubleByteList[0])
    PrintEightBitPattern("ADC output byte 2 = ", adcOutputDoubleByteList[1])

    adcDecimalValue = (adcOutputDoubleByteList[1] >> 1) + (adcOutputDoubleByteList[0] * (2 ** 7))

    # adcAnalogVoltage = (float(adcDecimalValue) / 4096) * 4.10 # without half voltage divider
    adcAnalogVoltage = ((float(adcDecimalValue) / 4096) * 4.10) * 2 # with half voltage divider
 
    print "Analog voltage = ", adcAnalogVoltage

When the dual digital potentiometer arrives, I think I will try some auto ranging as well.


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