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mete
Senior
November 3, 2023
Solved

hsi_ck should be hsi_ker_ck in the reference manual (0481)

  • November 3, 2023
  • 3 replies
  • 2340 views

In RM 0481 (STM32H563/H573) Rev 1, on page 444, Figure 48. Clock tree, HSI RC 64 MHz output is written as HSI (hsi_ck), whereas LSI and HSI48 outputs are named as lsi_ker_ck and hsi48_ker_ck. Since there is also a HSIDIV, and it is documented correctly (on page 471, RCC_CR register fields) mentioning hsi_ker_ck, I believe on the Figure 48, hsi_ck should be renamed to hsi_ker_ck.

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Best answer by STTwo-32

Hello again  

As you can see in the page 455 of the RM0481, We have 2 different paths for the HSI output. One for the system clock which is the hsi_ck. And one for the peripheral kernel clock which is the hsi_ker_ck. 

Best reagrds.

STTwo-32

3 replies

STTwo-32
Technical Moderator
November 5, 2023

Hello @mete and welcome to the ST Community :smiling_face_with_smiling_eyes:.

Thank you for your post. I'm checking this internally and I will get back to you as soon as possible.

Best regards.

STTwo-32

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.
STTwo-32
STTwo-32Best answer
Technical Moderator
November 6, 2023

Hello again  

As you can see in the page 455 of the RM0481, We have 2 different paths for the HSI output. One for the system clock which is the hsi_ck. And one for the peripheral kernel clock which is the hsi_ker_ck. 

Best reagrds.

STTwo-32

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.
mete
meteAuthor
Senior
November 6, 2023

Thanks, yes I realized both are used, so renaming the HSI output in the figure would be wrong. However, I still think it would be good to show this on the figure both for HSI and CSI. It is a bit confusing some (HSI48) outputs _ker some doesnt (HSI and CSI) but then _ker is used in other places (peripherals).

mete
meteAuthor
Senior
November 9, 2023

Just want to add that the reason for my question was mainly because I thought HSIDIV only works for hsi_ker_ck (I thought hsi_ck is the output before HSIDIV). I realized HSIDIV is active for both, so actually, I think, there is no way to get the HSI RC output before HSIDIV, so hsi_ck and hsi_ker_ck always have the same freq. I still think it would be a good idea to add HSIDIV to the clocktree (like other prescalers).