UART between NRF52 dev board and STM32F429ZI6 Discovery

RE: UART between NRF52 dev board and STM32F429ZI6 Discovery

StanB — Fri, 04 Nov 2016 16:01:51 GMT

I find out what it is, I tried on different uart on the stm32 and it works ! I tried usart1 and uart4 and it was not working, I suppose that the associated pins were used elsewhere on the discovery board and that it was interfering with the communication. usart2 works fine

RE: UART between NRF52 dev board and STM32F429ZI6 Discovery

Hung Bui — Fri, 04 Nov 2016 13:34:37 GMT

The STM should not drive the RX pin. Otherwise it won't be able to receive anything. You can test by connecting the TX pin of the 52 to smth else and see if it's toggle.

I haven't used the STM32, but it should have similar architecture with the NRF5 that the TX and RX interrupt has the same interrupt handler but different interrupt flag. You can check the flag and see which event is arrived. Same level interrupt won't preempt the other.

RE: UART between NRF52 dev board and STM32F429ZI6 Discovery

StanB — Thu, 03 Nov 2016 12:33:05 GMT

Hi HungBui,

the tx and rx use the same interruption handler so I don't think it can do a loopback, no ? I mean is it possible that the transmission interupt is interupt by the same interupt routine but for the reception ? The exemple for the STM is made for two boards. I test the STM uart connection only with my computer through usb and it worked perfectly fine so that lead me to think that the problem is on the pin configuration. I don't have an analyzer yet (I will order one) but I tried to set the nRF52 tx pin to low after the communication to see with a voltmetre if it's what happen but the state is high. It seems that the rx pin on the STM side force its state to high and the nRF is not able to change it... I don't know if what I am saying is clear

RE: UART between NRF52 dev board and STM32F429ZI6 Discovery

Hung Bui — Thu, 03 Nov 2016 11:26:52 GMT

Hi StanB,

Have you tried to do loopback test with the STM ? Just to check if the configuration was correct and you can receive RX interrupt ?

Have you tried to hook up a logic analyzer and check if the nRF52 sending something back to your STM ?