如何从树莓派3b +上的MCP3202读取SPI值？

Question

我正在尝试对树莓派3进行编程以从ADC（mcp3202）读取spi值

我提到了

https://learn.sparkfun.com/tutorials/python-programming-tutorial-getting-started-with-the-raspberry-pi/experiment-3-spi-and-analog-input

但是本教程使用的mcp3002 10bit ADC与我尝试实现的mcp3202 12bit ADC不同

那么我需要对此进行哪些更改

def read_adc(adc_ch, vref = 3.3):

    # Make sure ADC channel is 0 or 1
    if adc_ch != 0:
        adc_ch = 1

    # Construct SPI message
    #  First bit (Start): Logic high (1)
    #  Second bit (SGL/DIFF): 1 to select single mode
    #  Third bit (ODD/SIGN): Select channel (0 or 1)
    #  Fourth bit (MSFB): 0 for LSB first
    #  Next 12 bits: 0 (don't care)
    msg = 0b11
    msg = ((msg << 1) + adc_ch) << 5
    msg = [msg, 0b00000000]
    reply = spi.xfer2(msg)

    # Construct single integer out of the reply (2 bytes)
    adc = 0
    for n in reply:
        adc = (adc << 8) + n

    # Last bit (0) is not part of ADC value, shift to remove it
    adc = adc >> 1

    # Calculate voltage form ADC value
    voltage = (vref * adc) / 1024

    return voltage