The MSPM0 has a general purpose amp (GPAMP). It's an internal OpAmp that, for example, can buffer a signal for the ADC without external components. That's an example that I'm trying out in this post. Roughly based on the Resource Explorer gpamp_buffer_to_adc example.
Setup
For this example, the GPAMP is configured with x1 gain (a buffer or input follower). And its output is internally routed to the ADC input.
source: wikipedia all rights released (Public domain)
GPAMP settings:
The non-inverting input (+) is routed to pin PA26. The output is internally routed to the inverting input (+).
The internal routing to the ADC is done by setting the ADC channel:
The C code is unchanged from TI's gpamp_buffer_to_adc example.
|
ChatGPT info:
|
Test
The test source is a 2.5 V reference. The ADC reference is VDDA (3.3 V). I've done 3 tests: measure the ADC reference voltage, and the 2.5 V test signal.
- buffered by GPAMP,
- directly to the ADC
- with a Brymen BM235 DMM
| GPAMP (0 - 4095) | ADC (0 – 4095) | BM235 (mV) | ||||
| ADC ref | 4085 | 4095 | 3290 | |||
| input | 3110 | 0.761321909424725 | 3097 | 0.756288156288156 | 2498 | 0.759270516717325 |
This will work for the EasyL1105 board and with an L1306 Launchpad.
Thank you for reading.
