2020-04-06 01:24 AM
I did set up a basic STM32_CubeIDE project with 3 USARTs.
When the PB11 Pin (USART3 RX) is connected to the communication signal, the signal is corrupted to a high signal level of 2.6V and a low signal level of 1.7V. This also happens also, when I configure the PB11 Pin as a General Input Pin.
The Tx Signal of USART3 on PB10 and UART1 and UART2 are working correctly.
In the Errata sheet STM32L412xx I found the following comment about PB11:
"On 48-pin devices with SMPS support, the non-bonded PB8 and PB11 GPIOs remain software configurable."
As far as I can see in the datasheet, there is no 48-pin device with SMPS support. But the "non-bonded" comment worries me a bit - does this mean, on this device the PB11 Pin is really not connected and so the USART3RX function is not working at all (not published in the errata)?
2020-04-06 10:57 PM
In the meantime, I found out, that an SMPS-Type of the 48-pin housing exists, and this type was on my board (SMT32L412CBT6P). This explains the behaviour...