Knowledge Base

The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.

Knowledge Base

ADC-DAC Pi Zero with Raspberry Pi Pico

Using the ADC-DAC Pi Zero with Raspberry Pi Pico and MicroPython

The ADC-DAC Pi Zero can be used with the Raspberry Pi Pico available at www.raspberrypi.com/products/raspberry-pi-pico/

We have a MicroPython library to use with the Raspberry Pi Pico at GitHub at github.com/abelectronicsuk/ABElectronics_MicroPython_Libraries

The example Python files can be found in /ABElectronics_MicroPython_Libraries/ADCDACPi/demos/

Connecting the ADC-DAC Pi Zero to the Raspberry Pi Pico

The ADC-DAC Pi Zero library uses the following pins on the Raspberry Pi Pico board.

Pico Pin Pico GPIO Function Pi Pin Pi GPIO
4 GP2 SPI SCK 23 GPIO 11
5 GP3 SPI0 TX 19 GPIO 10
6 GP4 SPI0 RX 21 GPIO 9
7 GP5 ADC SPI CE0 24 ADC SPI CE0
25 GP19 DAC SPI CE1 26 GPIO 7
40 VBUS 5V 2 5V Power
38 GND GND 6 Ground
36 3V3(OUT) 3V3 1 3v3 Power

To use a different pin, you can edit the ADCDACPi.py on lines 24 to 36.


Wiring Diagram:

Downloading and Installing the library

To download to your Raspberry Pi, type in the terminal:

git clone https://github.com/abelectronicsuk/ABElectronics_MicroPython_Libraries.git

To install the MicroPython Library, use the Thonny Python IDE from https://thonny.org/

Create a file for your chosen board and copy the contents of the Python file into that board's directory. For example, for the ADC-DAC Pi, create a new file in thonny called ADCDACPi.py, copy contents from ADCDACPi.py into the new file, and save it onto the Raspberry Pi Pico board.

Create a second file where your main program will reside and import the board library at the program's top.

from ADCDACPi import ADCDACPi

Run with "Run Current Command" or F5 in Thonny.


Functions:

Initialising the ADCDACPi object.

adcdac = ADCDACPi(gain_factor)

Parameter: gain_factor - 1 or 2 When the gain is set to 1, the voltage range of the DAC will be 0 to 2.048V. When the gain is set to 2, the voltage will be 0 to 3.3V


read_adc_voltage(channel, mode) 

Read the voltage from the selected channel on the ADC
Parameter: channel - 1 or 2
Parameter: mode - 0 = single-ended, 1 = differential
Returns: number as a float between 0 and 2.048


read_adc_raw(channel, mode) 

Read the raw value from the selected channel on the ADC
Parameter: channel - 1 or 2
Parameter: mode - 0 = single-ended, 1 = differential
Returns: int


set_adc_refvoltage(voltage)

Set the reference voltage for the analogue to digital converter.
The ADC uses the raspberry pi 3.3V power as a voltage reference, so using this method to set the reference to match the exact output voltage from the 3.3V regulator will increase the accuracy of the ADC readings.
Parameters: voltage
Returns: null


set_dac_voltage(channel, voltage)

Set the voltage for the selected channel on the DAC. The DAC has two gain values, 1 or 2, which can be set when the ADCDAC object is created. A gain of 1 will give a voltage between 0 and 2.047 volts. A gain of 2 will provide a voltage between 0 and 3.3 volts.
Parameters: channel - 1 or 2, voltage - target DAC voltage
Returns: null


set_dac_raw(channel, value)

Set the raw value for the selected channel on the DAC
Parameters: channel - 1 or 2, value int between 0 and 4095
Returns: null

Usage

To use the ADC DAC Pi library in your code, you must first import the library:

from ADCDACPi import ADCDACPi

Next, you must initialise the adcdac object and set a gain of 1 or 2 for the DAC:

adcdac = ADCDACPi(1)

Set the reference voltage.

adcdac.set_adc_refvoltage(3.3)

Read the voltage from channel 2 and store it in a variable called x.

x = adcdac.read_adc_voltage(2)

Was this article helpful? Yes No

Please tell us how we can improve this article:

Submit
Created 27/10/2022 | Last Updated: 25/10/2023

Related Expansion Boards

Order a ADC-DAC Pi Zero Photo of ADC-DAC Pi Zero
ADC-DAC Pi Zero

2 Channel ADC and 2 Channel DAC for the Raspberry Pi

£14.99 Ex VAT: £12.49
Add to Cart

Related Articles

ADC DAC Pi with Python
ADCDAC Pi with Python on a Raspberry Pi
I2C Switch with Raspberry Pi Pico
Using the I2C Switch with Raspberry Pi Pico and MicroPython
ADC-DAC Pi Zero with Raspberry Pi Pico
Using the ADC-DAC Pi Zero with Raspberry Pi Pico and MicroPython