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[STM32F072] USART2 and USART4 does not work

Question asked by louis.herve on Apr 10, 2014
Latest reply on Apr 10, 2014 by louis.herve
Hello all,

I'm recently bought an STM32F072B-DISCO board (based on the STM32F072RBT6) and I'm currently testing it.
I'm really surprised to see that some USARTs doesn't work properly ; as mentioned in the errata sheet only USART4 has problem, but I noticed some problems on the USART2 and on the USART4.

Tests made separately on each USARTs

- USART1 :
    TX = PA9  ; RX = PA10 => Fully functional

    TX = PA2  ; RX = PA3  => It doesn't work (no TX and no RX)
    TX = PA2  ; RX = PA15 => Tx doesn't work, RX works
    TX = PA14 ; RX = PA3  => Tx works, RX doesn't work (but no possibility to debug due to PA14 = SWCLK)
    TX = PA14 ; RX = PA15 => Fully functional (but no possibility to debug due to PA14 = SWCLK)

- USART3 :
    TX = PB10 ; RX = PB11 => Fully functional

- USART4 :
    TX = PA0  ; RX = PA1  => TX doesn't work, RX works
    TX = PA0  ; RX = PC11 => It doesn't work (no TX and no RX)
    TX = PC10 ; RX = PA1  => Fully functional
    TX = PC10 ; RX = PC11 => TX works, RX doesn't work (see errata sheet)

Does anybody has the same problem ? This could exclude a software problem on my USARTs libraries... (please note that I used them on STM32F051 MCU and there was no problem).

@ST Team : The STM32F07x are new in production, do their USARTs have a stable behavior ? Do some of these have a specific configurations to use ?

Thanks a lot,