NRF UART RX done event only fires once

RE: NRF UART RX done event only fires once

thomac97 — Fri, 07 Jun 2019 15:48:11 GMT

So I found I rogue printf() in the UART ISR...upon removing the issue appears to be fixed. Apologies, I knew it would be something stupid. Thanks anyway

RE: NRF UART RX done event only fires once

Jørgen Holmefjord — Fri, 07 Jun 2019 15:30:22 GMT

Can you please provide the state of the registers in the UART(E) peripheral when this issue occurs? Do you get any errors in the event_handler?

RE: NRF UART RX done event only fires once

thomac97 — Mon, 03 Jun 2019 13:53:25 GMT

Hey Jorgen thanks for the reply.

I'm not currently writing or reading anything on the UART because I've been trying to debug this issue.

The Teensy I'm trying to communicate with is sending up to 1000 bytes (under normal conditions its at lot less, usually between 15 and 100 bytes) at 9600 baud. I've discovered that if I reduce the packet size being sent by the Teensy to 7 bytes or less with the SERIAL_BUFF_RX_SIZE defined as 1, the RX_DATA event works as expected. However if the packet is any larger, I get the issue described above which can be resolved by re-enabling the RXRDY interrupt flag, however this results in some data loss.

If I increase SERIAL_BUFF_RX_SIZE by a given amount, the packet size that causes the error increases by the same amount (i.e. for a SERIAL_BUFF_RX_SIZE of 2 the maximum packet size without causing an error is 8, for 3, it's 9 and so on).

Is there away to get around this? Or should I change the UART to polling mode? I need to keep SERIAL_BUFF_RX_SIZE defined as 1 because the received packet size will be variable, so I need the event to fire on every byte.

Thanks,

Thomas

RE: NRF UART RX done event only fires once

Jørgen Holmefjord — Mon, 03 Jun 2019 13:35:48 GMT

Hi,

Do you write anything on UART? In the code you attached, nrf_serial_read is commented out, and I can't see any other calls to this in your code. I tried commenting it out and running your code with nothing connected, and I hit a breakpoint inside NRF_SERIAL_EVENT_RX_DATA event multiple times.

Best regards,
Jørgen