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Configure STM32H750 ADC123 to simultaneously capture same channel in independent mode?

Sk11
Associate II

As the title suggests, the chip manual states that in dual ADC mode, ADC cannot be configured to simultaneously capture the same channel, but there is no explanation for independent mode. Is it feasible in independent mode? If not, what are the reasons behind it?

11 REPLIES 11
Sk11
Associate II

I have tried configuring ADC123 to simultaneously collect data from the same channel, and from the sampled data, there are no abnormalities. Does this mean it is feasible? If feasible, may long-term operation lead to internal hardware circuit problems?

First things to consider is accuracy. If the purpose of tripple sampling is to average and lower noise, than I don't think this is a good idea, since Rds of the selected channel != 0 than current to recharge S/H capacitors for all tree adc spikes x3, and the same apply to noise.

Secondly, all ADC share one Reference voltage source, and again triggering simultineously 3 adc generates distorbance /interference  for  each other. Even when they do convertion on separate channels.

I just want to verify the consistency of the three ADCs to improve the reliability of the system. Based on the current test results, there are no abnormalities in the original sampling data. Does this indicate that the proposed solution is feasible?The result is as follow.

Sk11_0-1733734806354.png

Sk11_1-1733734880520.png

 

 

Results are too good to be real, deep fake?

what uCPU board is in test?  

The result was actually tested and has been consistent multiple times. We are using a board that we have designed ourselves.

Sk11
Associate II

Can you help confirm? This is crucial for my current application. You can find a board to test it out

I don't understand a question. 

"reliability" of the system has nothing to do with simultenious sampling. 

In short, from hardware point of view you can sample three adc at once. 

Yes, what I want to know is whether it is possible to use three ADCs simultaneously to collect the same channel in independent mode from a hardware perspective. Why consider reliability? It's because we encountered a problem, and there are similar situations in the community, see link: https://community.st.com/t5/stm32-mcus-products/stm32h750vbt6-adc-16bit-14bit-issue/td-p/709534.

 

I have also encountered a similar problem where ADC1 channel data collection is abnormal. I have tried to modify various parameters, but none of them have been effective. However, when configuring ADC2 or 3 to collect the same channel data, the data is normal. Therefore, I suspect that ADC1 is the problem. So we want to use ADC123 to collect data simultaneously and verify each other to identify this issue

Just to add, I want ADC123 to collect the same channel simultaneously, which is allowed from a hardware perspective, right?