2022-08-31 07:52 AM
The output pin in question can be configured as LPTIM1_OUT and I know how to configure the LPTIM1 but I'm afraid I'll endup with LSE/2 as a clock. I need the LSE clock source to be connected to that output pin 1:1.
Besides using the LPTIM1 isn't there a more easy way to do this?
2022-08-31 08:08 AM
If LSE is activated, you can output its clock via pin MCO. The MCO output is preceded by a multiplexer and a divider. This allows you to select the clock in question, and the divider also allows you to select a divider ratio from 1:1...1:16.
Does it answer your question?
Regards
/Peter
2022-08-31 08:51 AM
Yes and no. Yes it answer my question but I realize my question is incomplete. The hardware is already fixed and I don't have any option to connect the peripheral to the MCO pin, it is connected to the LPTIM_OUT pin. The LSE clock source is much more accurate then the internal clock of the peripheral. Now we need to find a trick to get the LSE clock source connected to the LPTIM_OUT pin.
A hardware hack isn't the answer as the MCO pin is used for other functions, unfortunately.
2022-08-31 10:58 PM
Well, the RM0394, section 30.4.9 should give a clear answer here:
This results in exactly at least a halving of the input frequency, so that you cannot output LSE directly 1:1 from LPTIMx_OUT.
The only chance besides MCO would be RCC_LSCO - unfortunately you are stuck with LPTIMx_OUT.
Regards
/Peter