USB UART configuration has no RX

RE: USB UART configuration has no RX

awneil — Tue, 11 Dec 2018 08:05:18 GMT

[quote userid="75539" url="~/f/nordic-q-a/41384/usb-uart-configuration-has-no-rx/161100"]It's strange that at the same time we got the RX data in buffer[/quote]

Is it?

You showed your UART configuration, and it had NRF_UART_HWFC_DISABLED - so, as far as the UART hardware is concerned, its hardware flow control was disabled.

Therefore it is not surprising that the UART hardware did receive data.

Presumably, as noted earlier, this HWFC control must apply at some point further "up" the chain - towards (or within) the USB stuff.

You could pursue that by browsing/searching for the uses of that HWFC control ...

RE: USB UART configuration has no RX

Vladimir RB — Tue, 11 Dec 2018 02:11:38 GMT

We reviewed the code and found that hardwade flow control is used 🙂

After we changed next define we can send & receive data.

#define HWFC           false

It's strange that at the same time we got the RX data in buffer...

RE: USB UART configuration has no RX

Vladimir RB — Mon, 10 Dec 2018 16:44:30 GMT

You right, that if we received data from UART into buffer, that our problem has in another place 🙂

Because we don't change the example, we think that it should be an bug in initialization of USB UART. We still don't found it.

RE: USB UART configuration has no RX

awneil — Mon, 10 Dec 2018 10:28:44 GMT

So you're saying that you ran this in the debugger, and you do see the received data arriving in your UART handler?

If so, then that does go to show that your UART and UART handler are working - so your problem lies Further "up" the chain - towards the USB stuff ...

Have you looked at the Segger Monitor Mode Debugging for the time-critical parts ... ?

eg, https://devzone.nordicsemi.com/b/blog/posts/segger-embedded-studio-part-2-monitor-mode-debuggi - and search for other discusions ...

RE: USB UART configuration has no RX

Vladimir RB — Sun, 09 Dec 2018 17:50:00 GMT

We checked our receiving handler.

static void nbiot_read(struct nrf_serial_s const * p_serial,
                       nrf_serial_event_t event)
{
    switch(event)
    {
      case NRF_SERIAL_EVENT_RX_DATA:
      {
          nrf_serial_read(&serial_uart, &NBIOT_BUF[cntas], 1, NULL, 1000);  // читаем принятый байт UART в массив NBIOT_BUF
          //size_t size = sprintf(m_tx_buffer, &NBIOT_BUF[cntas]);
          //if (usb_open)
          //{
              app_usbd_cdc_acm_write(&m_app_cdc_acm, &NBIOT_BUF[cntas], 1);
              //nbiot_clr_buf(); //чистим буфер
          //}
          break;
      }
      default: break;
    }
}

We got the message in NBIOT_BUF.So our UART config should be correct.

RE: USB UART configuration has no RX

Vladimir RB — Sun, 09 Dec 2018 17:06:43 GMT

We checked that we use correct flow and speed configuration: 9600, No Hardware flow.

NRF_SERIAL_DRV_UART_CONFIG_DEF(m_uart0_drv_config,
                      TXD_BC68, RXD_BC68,
                      NRF_UART_PSEL_DISCONNECTED, NRF_UART_PSEL_DISCONNECTED,
                      NRF_UART_HWFC_DISABLED, NRF_UART_PARITY_EXCLUDED,
                      NRF_UART_BAUDRATE_9600,
                      UART_DEFAULT_CONFIG_IRQ_PRIORITY);

[quote userid="6462" url="~/f/nordic-q-a/41384/usb-uart-configuration-has-no-rx/160850"]No - each side has control of the other[/quote]

Where we can check it? I see initialization in only one place.

RE: USB UART configuration has no RX

awneil — Sun, 09 Dec 2018 12:24:26 GMT

[quote userid="75539" url="~/f/nordic-q-a/41384/usb-uart-configuration-has-no-rx/160849"]We doesn't run the debugger because USB is the time critical protocol and it will be crashed when we going into point.[/quote]

But you said that you have the same problem without USB - so use the debugger in that case!

[quote userid="75539" url="~/f/nordic-q-a/41384/usb-uart-configuration-has-no-rx/160849"]We don't use hardware control[/quote]

I can see that.

But have you correctly configured the UART to not use it?

The Nordic examples are designed to work with the Segger VCP - and that does require it ...

[quote userid="75539" url="~/f/nordic-q-a/41384/usb-uart-configuration-has-no-rx/160849"]Data flow control, as I understand, affect on both RX & TX at the same time[/quote]

No - each side has control of the other

RE: USB UART configuration has no RX

Vladimir RB — Sun, 09 Dec 2018 11:31:40 GMT

We don't use hardware control.

We tried to connect the nRF UART directly to end device. Rusult was the same.

We doesn't run the debugger because USB is the time critical protocol and it will be crashed when we going into point.

The main question there, as I understand, why after changing the pins we can't receive the data, while we still can transfer. Data flow control, as I understand, affect on both RX & TX at the same time. So if we can send data, that configuration is correct.

RE: USB UART configuration has no RX

awneil — Sun, 09 Dec 2018 11:11:13 GMT

Have you disabled hardware flow control?

Have you tried just the nRF UART part - without any USB?

Does the debugger show data being received by the nRF?