ADC Vref?

[vitthal muddapur]

Posted on May 05, 2018 at 11:02

Hi,

I beginner in stm32 i am using stm32l071 adc channel 9 

what is vref ?

vref is Vdda 

i am connect vdda as 2.5v this is internally connected to vref yes or not?

can i enable vref by software(in code)?

Sampling time variation gets different adc values  

Thanks and Regards

Vitthal R

[Tesla DeLorean]

Posted on May 05, 2018 at 16:21

VREFINT is Channel 17 (ADC_IN17) and nominally 1.224V

http://www.st.com/content/ccc/resource/technical/document/datasheet/b5/24/80/11/51/59/47/f7/DM00141136.pdf/files/DM00141136.pdf/jcr:content/translations/en.DM00141136.pdf

 

Channel 9 looks to be PB1 ADC_IN9, and VREFOUT can be output there

My understanding of the documentation is that you can route the VREFINT out of PB0 and/or PB1 so you can measure it with test equipment, and over voltage, temperature, etc.

http://www.st.com/content/ccc/resource/technical/document/reference_manual/21/bd/0f/bd/1c/88/40/f0/DM00108282.pdf/files/DM00108282.pdf/jcr:content/translations/en.DM00108282.pdf

 

[vitthal muddapur]

Posted on May 07, 2018 at 14:20

Hi,

can use PB1 as Analog input?

in analog input can i set pull-up or pull-down or no pull-up and pull-down 

[Tesla DeLorean]

Posted on May 07, 2018 at 14:43

>>can use PB1 as Analog input?

I think we established it was ADC_IN9 in the previous post.

>>in analog input can i set pull-up or pull-down or no pull-up and pull-down 

You'd really want to avoid having it pull up/down, wouldn't you?

I'd set the PUPDR bits to 00

[vitthal muddapur]

Posted on May 07, 2018 at 14:58

hi,

I configured ADC_IN9 as anlog input but not get current reading compare with input voltage