Implementation of the interface to use the MCP3xxx family in Micropython

mcp.py

class MCP:
    def reference_voltage(self) -> float:
        """Returns the MCP3xxx's reference voltage as a float."""

        raise NotImplementedError

    def read(self, pin: int | None = None, is_differential=False) -> int:
        """
        read a voltage or voltage difference using the MCP3102.

        Args:
            pin: the pin to use
            is_differential: if true, return the potential difference between two pins,


        Returns:
            voltage in range VREF

        """

        raise NotImplementedError


class MCPSerialInterface(MCP):
    def __init__(self, spi, cs, ref_voltage=3.3):
        """
        Create MCP SPI instance

        Args:
            spi: configured SPI bus
            cs:  pin to use for chip select
            ref_voltage: r
        """
        self.cs = cs
        self.cs.value(1)
        self._spi = spi
        self._out_buf = bytearray(3)
        self._out_buf[0] = 0x01
        self._in_buf = bytearray(3)
        self._ref_voltage = ref_voltage

    def reference_voltage(self) -> float:
        return self._ref_voltage
    
    @property
    def buffers(self):
        return self._out_buf, self._in_buf


class MCP3202(MCPSerialInterface):
    def read(self, pin=None, is_differential=False):
        self.cs.value(0)
        self._out_buf[1] = ((not is_differential) << 7) | (pin << 4)
        self._spi.write_readinto(self._out_buf, self._in_buf)
        self.cs.value(1)

        return ((self._in_buf[1] & 0x0F) << 8) + self._in_buf[2]


class MCP3301(MCPSerialInterface):
    def read(self, pin=None, is_differential=False):
        self.cs.value(0)
        self._out_buf[1] = 0x00
        self._spi.write_readinto(self._out_buf, self._in_buf)
        self.cs.value(1)
                
        signal = ((self._in_buf[0] << 8) | self._in_buf[1]) & 0x1FFF

        if signal & 0x1000:
            signal -= 0x2000
        
        return signal

mcp_example.py

import time

from machine import SPI, Pin
from mcp import MCP3102

if __name__ == '__main__':
    spi = SPI(1, sck=Pin(10), mosi=Pin(11), miso=Pin(12), baudrate=400000) # for Raspberry Pi Pico
    cs = Pin(13, mode=Pin.OUT, value=1)

    mcp = MCP3102(spi, cs)

    if __name__ == "__main__":
        while True:
            print("Value: ", mcp.read(0))
            time.sleep(0.05)