Hello @waclawek.jan
Detailed update.
More tests are done internally with the following STM32F4 part numbers:
| Product |
OSC_OUT in HSE_BYPASS |
| F407VG |
Not available |
| F429ZI |
Not available |
| F439ZI |
Not available |
| F469NI |
Not available |
| F413ZH |
Working |
| F446ZE |
Working |
| F401RE |
Not available |
| F410RB |
Working |
| F411RE |
Not available |
| F412ZG |
Working |
So only the latest F4 products from F446, F410, F412 and F413 are able to use PH1 (or PF1) as GPIO independently when RCC is in HSE_BYPASS mode.
After discussion with the design, and as you said @waclawek.jan that's something linked to STM32 history and the F4 family was developed by different design teams during several years period.
Unfortunately, the GPIO characteristics of PH1 in this condition is not tested and cannot be confirmed to be safely used as a standard GPIO based on specification in the datasheet.
This is why our Reference Manual, indicates External source in HSE bypass, the PH1 (or PF1) act as OSC_OUT and the pin should be left in HI-Z state.
So we cannot guarantee using PH1 in this way, as we do not test either in validation and in production.
Based on this, all the F4 device family, PH1 must be left unconnected and we do not recommend using it as GPIO when RCC is in HSE_BYPASS mode.
On STM32CubeMX side, nothing to change with the actual config.
However, no constraint and no limitation to use PH0 and PH1 in GPIO if RCC use HSI.
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