MCP342x

Simple class based access to the MCP342x series A/D converters in Python

Includes classes for the MCP3425, MCP3426, MCP3427, and MCP3428

quick example:

import time                                                                                           
import mcp342x                                                                           

# get access to a specific device on a bus                                                             
i2c_bus_number = 1
device_address = 0x68
my_adc = mcp342x.Mcp3426(i2c_bus_number, device_address)

# add an input channel to the device                                                                   
channel_number = 0
first_input = mcp342x.Channel(my_adc, channel_number)

#configure channel for 12bit continuous mode and exercise it                                           
print('continuous mode')
first_input.sample_rate = 240
first_input.pga_gain = 1
first_input.continuous = True

first_input.start_conversion() # update device with current channel state and start acquisition        
time.sleep(first_input.conversion_time)
volts = first_input.get_conversion_volts()
print('Chan{}: Volts={}'.format(first_input.number, volts))

Dependencies

• Uses smbus2

Notes

• Tested with both an MCP3426 and MCP3428, primarily in continuous mode, on a raspberry pi zero w.
• Naming conventions follow the Microchip data sheet as best as possible.
• Module does not call time.sleep(). Timing is the responsibility of the application.
• Raises I2CBussError with some help on i2c related OSError.
• Raises ConversionNotReadyError if the not ready flag is found set while reading a conversion.

Todo

• look into passing a smbus2 instance rather than a bus number to Mcp342x.
• identify differences in the MCP3422 group of devices and add overrides for those if possible.