libuarte Unexpected RX free input parameter

RE: libuarte Unexpected RX free input parameter

JoEi — Tue, 08 Nov 2022 10:36:12 GMT

Hi Håkon,

I've tested a few things and the problem was as you've said calling NRF_LIBUARTE_ASYNC_DEFINE(..) with RTC and TIMER for the timeout. After removing the TIMER instance for the timeout libuarte works perfectly.

Thanks for your help =)

Kind regards,
Johannes

RE: libuarte Unexpected RX free input parameter

JoEi — Tue, 25 Oct 2022 09:32:42 GMT

Hi Håkon,

[quote userid="2115" url="~/f/nordic-q-a/93058/libuarte-unexpected-rx-free-input-parameter/392312"]What is the "libuarte" variable here?[/quote]

libuarte is the variable I got from NRF_LIBUARTE_ASYNC_DEFINE.

[quote userid="2115" url="~/f/nordic-q-a/93058/libuarte-unexpected-rx-free-input-parameter/392312"]It looks like context is going out of scope at your end. Could you try storing uart_event_handler::context and using that instead of "&libuarte"?[/quote]

I've tried that before when implementing libuarte but back then I couldn't get it to run. According to my logs from back then I only got unexpected libuarte events

[quote userid="2115" url="~/f/nordic-q-a/93058/libuarte-unexpected-rx-free-input-parameter/392312"]Sorry, the logic was misread from my side. This is on a byte-for-byte basis, so 100 us is fine here.[/quote]

I've changed the timeout to 1ms and so far I haven't seen the error again. But instead on the usb side something behaves strangely now.

Kind regards,
Johannes

RE: libuarte Unexpected RX free input parameter

Håkon Alseth — Tue, 25 Oct 2022 08:18:11 GMT

Hi Johannes,

[quote user="Johannes"]A1: Only if I unplug or plug in the uart connector when the bridge is already running, which normally isn't the case.[/quote]

Ok, that is to be expected. You can add a re-init routine to recover from that scenario, if wanted.

[quote user="Johannes"]A2: I've found an example that configured the libuarte like this and haven't thought much about it.[/quote]

You should select either RTC based timing, or high speed TIMER.

[quote user="Johannes"]A3: Well I used the same timeout that is used in the libuarte example in the SDK. Is there a rule of thumb how to choose the right timeout?[/quote]

Sorry, the logic was misread from my side. This is on a byte-for-byte basis, so 100 us is fine here.

The usual scenario when receiving "Unexpected RX free input parameter" is that there is a timing issue in the firmware, wrong input parameter, etc.

Looking at your code here:

static void uart_event_sched_handler(void* p_event_data, uint16_t event_size)
{
  nrf_libuarte_async_evt_t* p_evt = (nrf_libuarte_async_evt_t*) p_event_data;

  switch(p_evt->type)
  {
    case NRF_LIBUARTE_ASYNC_EVT_RX_DATA:
    {
      u8* pu8Data;
      u32 i;
      for(i = 0, pu8Data = p_evt->data.rxtx.p_data; i < p_evt->data.rxtx.length; i++, pu8Data++)
      {
        UART_RxProcess(*pu8Data);
      }
      nrf_libuarte_async_rx_free(&libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);

What is the "libuarte" variable here? normally, you want to pass both the void pointer and the p_evt coming from the libuarte evt handler:

void my_libuarte_handler(void * context, nrf_libuarte_async_evt_t * p_evt)
{
    nrf_libuarte_async_t * p_libuarte = (nrf_libuarte_async_t *)context;
    switch (p_evt->type)
    {
    case NRF_LIBUARTE_ASYNC_EVT_RX_DATA:
        nrf_libuarte_async_rx_free(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);
        ...
}

It looks like context is going out of scope at your end. Could you try storing uart_event_handler::context and using that instead of "&libuarte"?

Kind regards,

Håkon

RE: libuarte Unexpected RX free input parameter

JoEi — Mon, 24 Oct 2022 13:09:20 GMT

Hi Håkon,

A1: Only if I unplug or plug in the uart connector when the bridge is already running, which normally isn't the case.

A2: I've found an example that configured the libuarte like this and haven't thought much about it. 😅

A3: Well I used the same timeout that is used in the libuarte example in the SDK. Is there a rule of thumb how to choose the right timeout?

Kind regards,
Johannes

RE: libuarte Unexpected RX free input parameter

Håkon Alseth — Mon, 24 Oct 2022 12:33:24 GMT

Hi,

Q1: Does the event "NRF_LIBUARTE_ASYNC_EVT_ERROR" occur at some point?

Q2: You seem to configure NRF_LIBUARTE_ASYNC_DEFINE(..) to use both RTC and high speed TIMER for timeout generation, is this intended?

Q3: The timeout is set to 100 us. This sounds a bit low for receiving up to 256 bytes payload. Have you tried adjusting this a bit higher?

Kind regards,

Håkon

RE: libuarte Unexpected RX free input parameter

JoEi — Thu, 20 Oct 2022 12:47:15 GMT

Ok somehow Ozone showed me complete nonsense.

Sometimes I reach the point where rx_free_cnt is 250 and nrf_libuarte_async_rx_free is called with a length greater than 6 (e.g. 20) which results in rx_free_cnt exceeding the buffer size 256.