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Pavel Krupets
Pavel Krupets
Associate III
March 13, 2019
Question

STM32L151VE ADC in sequence reads higher value for the 1st rank

  • March 13, 2019
  • 3 replies
  • 787 views

ADC consistently reads higher value for any channel which is 1st in the sequence. If I query this channel 2nd time as rank 2 (immediately after high value) then it reads normal value. Value is high by about 10%.

Tested on stable input many-many times.

Is this normal?

This topic has been closed for replies.

3 replies

Uwe Bonnes
Uwe Bonnes
Chief
March 13, 2019

It is normal if you use too small sampling times.

Pavel Krupets
Pavel KrupetsAuthor
Associate III
March 13, 2019

Thank you!

It is a kind of interesting that while reading 24 channels in a sequence only 1st one gets it wrong. :)

Pavel Krupets
Pavel KrupetsAuthor
Associate III
March 13, 2019

This also reproduces if I use 16 MHz ADC clock with 16 cycles sampling time (original problem had 4 cycles).

It is not a big deal though as sampling the same channel again fixes the problem.

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