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Triggering measure from ADC via software trigger

An ADC, or Analog-to-Digital Converter, is a crucial component in modern electronics that converts continuous analog signals into discrete digital data. In simpler terms, it takes real-world phenomena, like sound or temperature, and turns them into numbers that a computer can understand and process. This conversion is essential for various applications, in power electronics it allows us to get real-time measures from the circuit like voltage and current.

This example will show you how to get measures from the ADC by calling a function that will trigger the measures : this is what we call a software trigger.

Hardware setup and requirements

Schematic

You will need :

  • 1 spin
  • A usb-c cable to supply power to the spin, and also upload the code from computer
  • A signal generator to create a waveform to measure it from ADC, it can be sinewave, triangle wave...etc. This signal must between 0V and 2.048V

Connect the signal generator to pin C4, and gnd.

Software setup

The ADC 2 is used here, it is initialized like this : 

    spin.adc.configureTriggerSource(2, software); // ADC 2 configured in software mode
We use the 5th channel of the adc, which is the gpio C4 on the spin (also numbered as pin 35). To enable the acquisition from this pin, we use the function enableAcquisition: 

data.enableAcquisition(2, 35) // Enable acquisition for ADC2, for channel 5 (localized in GPIO C4 / pin number 35)
When we want to retrieve measures from ADC2 all we need to do is trigger ADC2 and retrieve measured value in GPIO C4 / pin number 35 :

    data.triggerAcquisition(2);
    adc_value = data.getLatest(2, 35);

There is a total of 8 possible pin from where you can get analog measures :

GPIO PIN number ADC and channels
PC4 35 ADC2 channel 5
PA1 30 ADC1 channel 2 / ADC2 channel 2
PA0 29 ADC1 channel 1 / ADC2 channel 1
PC3 27 ADC1 channel 9 / ADC2 channel 9
PC2 26 ADC1 channel 8 / ADC2 channel 8
PC1 25 ADC1 channel 7 / ADC2 channel 7
PC0 24 ADC1 channel 6 / ADC2 channel 6
PB15 6 ADC4 channel 5

You can configure any of the above ADC with same steps.

Expetected results

The analog value measured from the adc is stored inside the variable adc_value, which is printed in the serial monitor every 100ms you can then watch the measured on ownplot.

If everything went correctly, you should observe the same waveform on ownplot that you generate via the signal generator.