NRF52832 FreeRTOS+UARTE not worked

[Lurn_Z]

Hi everyone:

I want to use UARTE on my FreeRTOS, but when I used the example(examples/peripheral/libuarte) in rtos, something went wrong.

First of all, I tested the example, and it looks like good. When I send slowly, the uart log is here.

and when I send quickly(every 4ms), the uart log is that.

But when I use the UARTE in FreeRTOS, It looks OK when sending slowly, but when I send it every 4ms(I need this frequency), the result is here.

I don't know what's wrong.

Best regards, 

Lurn

[Einar Thorsrud]

Hi Lurn,

There is not much to go on here. Can you elaborate a bit more? How exactly do you doing things in your implementation, and what exactly happens in the failing case? And what is the difference between the failing case (with FreeRTOS) and without it?

Generally FreeRTOS does not interfere directly with UART, but it is tempting to think that there could be some issue with priorities, perhaps the application now is doing more or for some reason is not able to service UART related interrupts fast enough, but I don't know enough of your application to be more specific.

[Lurn_Z]

Sorry for my unclear description.

I use the example uarte code in FreeRTOS, just modify here

    nrf_libuarte_async_config_t nrf_libuarte_async_config = {
            .tx_pin     = TX_PIN_NUMBER,
            .rx_pin     = RX_PIN_NUMBER,
            .baudrate   = NRF_UARTE_BAUDRATE_921600,
            .parity     = NRF_UARTE_PARITY_EXCLUDED,
            .hwfc       = NRF_UARTE_HWFC_DISABLED,
            .timeout_us = 2,
            .int_prio   = APP_IRQ_PRIORITY_HIGH,
            .pullup_rx  = 1
    };

I change the int_prio from APP_IRQ_PRIORITY_LOW to APP_IRQ_PRIORITY_HIGH.

the question is when I use FreeRTOS,when I'm done sending the data, I should receive the data immediately, the log should like that,  (the ->◇ is send data, <-  is receive data).

Lurn_Z said:

But now, I get a wrong state, I only receive some data after I send it several times

Lurn_Z said:

BR,

Lurn

[Lurn_Z]

you can see the application in examples/peripheral/blinky_freertos/pca10040/blank/arm5_no_packs.

I removed a lot of things that were not related to UART. So, maybe it looks like a bit of a mess.

6683.nRF5_SDK_17.1.0.zip

BR,

Lurn

[Lurn_Z]

maybe you need to modify the start address, because in another ticket I need program MBR, so I modify it to 0X1000.

[Lurn_Z]

Hi Einar,

Did you find anything in my application?

I can't find the reason for this question.

BR,

Lurn

[Einar Thorsrud]

Hi Lurn,

I have not tested your application on my end, but I have had a closer look, and the UART related code seems good to me.

The screenshot you showed where many Z characters were received seems to indicate that there is no data loss, though - only that you got two events for what I assume conceptually was one transaction? You will get data when there is a timeout (packet boundary) or when the Rx buffer is full. What happens if you adjust the timeout here in your uart_init() function?

Einar

[Lurn_Z]

I modify the timeout to 10 or 100 or 1000, it looks like same..

timeout is 100us in this logs.

 

[Lurn_Z]

Einar Thorsrud said:

here is no data loss, though - only that you got two events for what I assume conceptually was one transaction

Yes, I think so, the data is not lost, just became two parts.

Einar Thorsrud said:

You will get data when there is a timeout (packet boundary) or when the Rx buffer is full.

I think it's really about Rx buffer, cause when I change the buffer size from 256 to 64 the data was be split earlier.

NRF_LIBUARTE_ASYNC_DEFINE(libuarte, 0, 0, 0, NRF_LIBUARTE_PERIPHERAL_NOT_USED, 64, 3);

But, the rx buffer was cleared everytime I received data.

I used that nrf_libuarte_async_rx_free(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);

Do you have any other solution?

And I have another question that I need a frequency of 500 times per second, but when I test the application,I don't think it can reach this frequency. Because I get the logs in 9 second, it just 260 times data. Also I will check the sender frequency, and I hope you can give me some suggestions.

BR,

Lurn