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Is this uC damaged?1 ADC ch reflects its value on other 2

Question asked by Diego Colombo on Feb 23, 2018
Latest reply on Feb 26, 2018 by waclawek.jan

Hi ,i'm talking about STM32F410RBT
I'm using 12 ADC channels in DMA mode.I did any sort of manipulation around the hardware built on a prototype board,and it is not unlikely that something went wrong,despite only 3.3V are used.

The analog signals are very slow,i sample it at 1KHz

The acquired values are sent to an UART,at the pretty high speed of 460800 bps,and then a serial to USB converter send it to a PC where i wrote a primitive 12 channel minimal "oscilloscope viewer".
I tested each channel with an arbitrary function generator,then with some analog sensor and everything worked fine

Now what i see is that an ADC channel,say CH9,reflects its value on CH10 e CH11,that strangely does not move when a signal is applied to them.
I checked serial,USB and PC simply forcing known levels in the ADC out buffer.

I was in doubt that something was changed wrongly in my DMA acquisition,and that the fact that the affected channels were the last to be sampled was the reason.
So i exchanged them with CH0,CH1,CH2,but the problem still looks related to the "physical" ADC channels CH9,CH10,CH11.
I'm always prone to blame my code rather than a good uC,so i ask to you,in the community,if this behaviour is symptom of fault or wrong code,if you experimented it.
Many thanks for your attention

 

Diego,
Milan
Italy

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