XMC1400 P4_8 inverted behavior

[Rasenburger]

Hi, I am using XMC1400 Bootkit and Modus Toolbox. I am setting signals according to UART inputs (first two tracks) on 4 pins (6,7,8,9) of port 4 all defined in the same way on the BSP design.modus configurator and controlled with 4 identical pieces of code in the main.c but one of them, the P4_8 has inverted behavior (yellow track): it goes high when all others would go low.

Any idea what could be wrong ?

Thanks.

Julius

[Rasenburger]

As additional information I attach the configuration snapshot and traces at booting.

Pin 4_8 has a bounce and stays HI, also Pin 4_9 has a bounce but goes down.

It seems an anomalous behavior... any help ?

[Aashita_R]

Hi @Rasenburger ,

Apologies that the response to your query has been delayed. Due to the community algorithm, it might have been missed. I went through your mentioned issue and based on the two images which you have shared, I might suggest you to select the correct "Alternate functionality" for these pins 4_8 and 4_9. As shared from the device datasheet, these pins come up with below functionalities -

These are functioned to behave as USIC channels select lines, which happens to stay high in their usual state and then is pulled low if the corresponding device is selected in case of SPI . Can you please check the ALT value you are trying to use at your end and see if these pins would be helpful for UART? Otherwise, you can try using other pins for UART.

Please add here in case of any further query.

Best Regards,

Aashita