drivers/serial: stm32: Force oversampling value #31178
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When setting baudrate register, baudrate value is computed according to the oversampling given value, which is default boot time value (16). In case oversampling value has been changed by bootloader (as in case of TFM bootloader), a desynchronsation happens between OVR and BRR values and the ouptut baudarate is incorrect. For oversampling register before setting the baudrate to avoid this situation. Signed-off-by: Erwan Gouriou <[email protected]>
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@yestin should fix issue seen in #31118 (review) |
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"In case oversampling value has been changed by bootloader" --> could this value be set to LL_USART_OVERSAMPLING_8 (and no more the reset default value LL_USART_OVERSAMPLING_16) ? |
@FRASTM Default reset value is 16, so I guess this is a usual value. Besides, this value is in use since ages in multiple applications and no one complains, I would not dare to change this w/o heavy testing. |
FRASTM
approved these changes
Jan 8, 2021
dcpleung
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Jan 8, 2021
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When setting baudrate register, baudrate value is computed according
to the oversampling given value, which is default boot time
value (16).
In case oversampling value has been changed by bootloader (as in case
of TFM bootloader), a desynchronsation happens between OVR and BRR
values and the ouptut baudarate is incorrect.
For oversampling register before setting the baudrate to avoid this
situation.
Signed-off-by: Erwan Gouriou [email protected]