nRF52840 DK - UART Stops

RE: nRF52840 DK - UART Stops

AbdulSamad — Mon, 06 May 2019 06:19:40 GMT

Hello Edven,

It appears that I had a bit of an issue using the I2C functions when I was trying to read values from the sensor. It was a little difficult. Using the following functions helped in reading from and writing to the sensor.

char readBytes(char address, unsigned char *values, char length)
// Read an array of bytes from device
// values: external array to hold data. Put starting register in values[0].
// length: number of bytes to read
{
#if DEBUG_ENABLED
  NRF_LOG_INFO("Start readBytes");
  for (int i = 0; i < length; ++i)
    NRF_LOG_INFO("data[%d]: %02x", i, values[i]);
  NRF_LOG_FLUSH();
#endif
  ret_code_t _error = nrf_drv_twi_tx(&m_twi, address, values, 1, true);
  APP_ERROR_CHECK(_error);
#if DEBUG_ENABLED
  NRF_LOG_INFO("Waiting for transfer completion.");
  NRF_LOG_FLUSH();
#endif
  while (m_tx_done == false)
    ;
  m_tx_done = false;
  //#if DEBUG_ENABLED
  //  for (int i = 0; i < length; ++i)
  //    NRF_LOG_INFO("data[%d]: %02x", i, values[i]);
  //#endif
  if (_error == 0) {
    ret_code_t _error = nrf_drv_twi_rx(&m_twi, address, values, length);
    APP_ERROR_CHECK(_error);
    while (m_rx_done == false)
      ;
#if DEBUG_ENABLED
    NRF_LOG_INFO("Rx readBytes");
    for (int i = 0; i < length; ++i)
      NRF_LOG_INFO("data[%d]: %02x", i, values[i]);
    NRF_LOG_INFO("End readBytes\r\n");
    NRF_LOG_FLUSH();
#endif
    m_rx_done = false;

    return 1;
  } else
    return 0;
}

char writeBytes(char address, unsigned char *values, char length) {
  ret_code_t _error = nrf_drv_twi_tx(&m_twi, address, values, length, false);
  APP_ERROR_CHECK(_error);
  while (m_tx_done == false)
    ;
  m_tx_done = false;
  return 1;
}

As you can see, I'm using NRF_LOG_INFO() macros to speed up the debug (instead of UART).

I re-visited this part about 2 weeks ago and I couldn't remember the old issues I posted about 🙂 Thanks for the troubleshooting hints and also offering to reproduce the issue UART! Cheers

RE: nRF52840 DK - UART Stops

AbdulSamad — Sun, 10 Feb 2019 04:53:18 GMT

Hello,

Pardon the late reply! I've been caught up in a few other projects and looks like I'll have to come back to this in a while. Thank you for the debugging suggestions. I'll go through them one by one and post an update later.

RE: nRF52840 DK - UART Stops

Edvin — Thu, 31 Jan 2019 11:27:15 GMT

Hello,

How long does your application run before it stops responding?

I can't see anything obviously wrong with your setup. Can you test a couple of things?

Does it work, or work longer if you only use one of the UARTS?

Does the behavior change if you use the sleep_handler?

When it stops receiving, is the application still running through your main loop? Or does it stop somewhere?

Is there any way for me to reproduce this issue? Is it possible to zip the project that you use and send it so that I can test it on a DK? If so, can you give some instructions on how to reproduce? Note that I don't have the GPS, but maybe I can simulate one by sending messages through an UART terminal to the DK.

BR,

Edvin

RE: nRF52840 DK - UART Stops

AbdulSamad — Thu, 31 Jan 2019 06:15:40 GMT

Brief update on the progress:

I've tried a few things to see what's going on.

1. As I'm using two UARTs, I decided to change the VCP pins (UART0) to different pins on the board eg P0.30 and P0.31. No luck there. So, I reverted to original settings and use VCP as normal.

2. Temporarily, as I'm not using Rx pin on the GPS module, I decided to utilize it to send messages and use an FTDI chip to read the data from P0.31. It works for longer but it stops after 5-6 mins. Although the ret_code from nrf_serial_read is printed out on VCP, it's always showing up as 0x00 which indicates NRF_SUCCESS even after the output at P0.31 stops; I'm a bit dubious about how reliable this test can be given that VCP output stops even in the default serial example.

So, at this point, the questions that I have in mind are:

a. Is this problem due to the interface MCU as mentioned in some other posts? Is there any workaround for it? Is there any way to isolate the interface MCU after downloading the code?

b. Is there anything special needed for UART initialization?