UART and UARTE state after reset

RE: UART and UARTE state after reset

Einar Thorsrud — Thu, 04 Jun 2020 10:24:15 GMT

Hi,

I am glad you found the root cause. And thank you for letting us know, that can be useful for other as well.

RE: UART and UARTE state after reset

Johan_c — Thu, 04 Jun 2020 10:15:41 GMT

Hi,

Yes with soft reset i mean NVIC_SystemReset(sys_reboot() in zephyr)

I think i've figured it out now and its a zephyr issue.
We run a zephyr based bootloader and zephyr initializes the uart during boot up even if it is not used.
when the zephyr application starts it initalizes it again and clear the RXDRDY event without reading out a byte from the uart. this causes the uart to deadlock.

Thanks this case can be closed.

RE: UART and UARTE state after reset

Einar Thorsrud — Tue, 02 Jun 2020 12:38:41 GMT

Hi,

This is a bit surprising since all peripherals are reset during a soft reset, including the RDX register of the UART peripheral. Just to avoid confusion it would be good to confirm that by soft reset you mean NVIC reset (NVIC_SystemReset()), and not for instance a call to Reset_Handler?

RE: UART and UARTE state after reset

dav01 — Tue, 02 Jun 2020 08:33:21 GMT

I'm also curious about this!