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Optionally adjust the clock of the ADC

giwonKIM
Associate III

Hi I'm KIM from south Korea.

 

My MCU is "STM32H735ZGT6".

 

I want to change the clock of ADC1 within the code.

I set up the clock of ADC1 in CUBEMX Clock Configuration about 80Mhz, but I want the clock of ADC1 about 75Mhz.

 

How can I change the clock?

 

Thank you.

1 ACCEPTED SOLUTION

Accepted Solutions
Peter BENSCH
ST Employee

The maximum permissible frequency fADC does not refer to the resolution, but to the implementation of ADC1 and ADC2. ADC1/2 are therefore limited to max. 50MHz with ADC_CR_BOOST=11, fADC of ADC3 is unaffected by this and can be set up to 75MHz.

This also answers your second question: a clock frequency higher than 50MHz can only be used with the ADC3.

Regards
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

View solution in original post

4 REPLIES 4
Peter BENSCH
ST Employee

Please share your IOC so that we can take a look at it, because the clock of ADC1 may be a maximum of 50MHz depending on the setting.

Regards
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

I checked that 16bits ADC is up to 50MHz in the datasheet.

 

But if I use ADC1 or ADC2 as 12bits ADC, can I use it up to 75MHz?

 

If I want to use 75MHz, is the only way to use ADC3?

Peter BENSCH
ST Employee

The maximum permissible frequency fADC does not refer to the resolution, but to the implementation of ADC1 and ADC2. ADC1/2 are therefore limited to max. 50MHz with ADC_CR_BOOST=11, fADC of ADC3 is unaffected by this and can be set up to 75MHz.

This also answers your second question: a clock frequency higher than 50MHz can only be used with the ADC3.

Regards
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

Thank you. 

 

I will refer to your advice.