RE: nrf52832 uart tx problem

MartinBL — Fri, 12 Oct 2018 14:45:34 GMT

Hi,

You need to clear the ENDTX event after your first transfer. Otherwise ENDTX = 1 once you start your next transfer and the code doesn't stop in the second while (NRF_UARTE0->EVENTS_ENDTX == 0) loop, but powers through instead, and stops the UART before the second transfer has started.

...
NRF_UARTE0->TXD.MAXCNT = 2 ; 
NRF_UARTE0->TXD.PTR = (uint32_t)&bno_tx_buf[0];
NRF_UARTE0->TASKS_STARTTX = 1;
while (NRF_UARTE0->EVENTS_ENDTX == 0)
{
}
NRF_UARTE0->EVENTS_ENDTX = 0; // <- CLEAR ENDTX EVENT AFTER USE

NRF_UARTE0->TASKS_STOPTX = 1;
while (NRF_UARTE0->EVENTS_TXSTOPPED == 0);

//delay

NRF_UARTE0->TXD.MAXCNT = 2 ; 

NRF_UARTE0->TASKS_STARTTX = 1;
...