Use nrf_drv_uart.h or nrf_drv_uarte.h to allow a 921600 baud rate with double Rx buffer

[tomasalar]

I am willing to use the uart or uarte driver to be able to have to buffers for the Rx, I have a huge flow of data at high sped arriving to the UART, I have read for few days the forum, and could not find a tidy example that use the driver with aot the app_uart. But it is mentioned in many of them that is the only approach to be able to have to buffers of 256 bytes available to avoid loose of data. I have check the documentation in:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v15.2.0%2Fhardware_driver_uart.html&cp=4_0_0_2_0_19

But I am struggling to bring it in to my code. I am working in a team and the Uart was implemented for a colleague using the app_uart, but for some reason we are loosing between 6 to 20 bytes and seems is because the MCU is not able to handle the data arriving on time.

If you have a simple example (non of those in SDK 16 i found useful) would be really a help.

Thank you so much for your support

Best Regards,

Tomas

[Jørgen Holmefjord]

Hi,

You will need to use the UARTE peripheral to use double-buffering and 255 bytes buffers. Unfortunately, there are no examples in the SDK that uses the UARTE driver directly. Do you have HW flow control (RTS/CTS pins) between the two devices? If not, I would recommend you to have a look at the libUARTE library and example. This library provides reliable communication over UART.

Best regards,
Jørgen

[tomasalar]

We are trying to use the example, but we modify the handler to get the data from the 

p_evt->data.rxtx.p_data,
p_evt->data.rxtx.length,

directly to an external buffer that is bigger, about 5000 bytes.

Are we doing it wrongly? :

case NRF_LIBUARTE_ASYNC_EVT_RX_DATA:
for(i = 0; i < p_evt->data.rxtx.length; i++)
        {
             _iwr6843_sensor_dataTom[i + nextpoint] = *(p_evt->data.rxtx.p_data+i);
                                    
        }

We are getting the software stuck when trying to stop the uart and do other process in the main like simple print the data in _iwr6843_sensor_dataTom, it shows:

Any Ideas for what we could be handling wrong?

[Jørgen Holmefjord]

I'm not sure if that code alone can put you in the error handler. Have you tried to build the application with the Debug configuration, and check the log output for details on which function is reporting an error?

[tomasalar]

How do I do it, I thought we were using the debug configuration in the SES, or shall I define something in my code? 

[Jørgen Holmefjord]

You can choose the build configuration, release or debug, in the upper left corner in SES:

If you are using the libUARTE example, logging over RTT should be enabled by default. You can read the logs using J-Link RTT Viewer. It is also possible to view the logs in the debug terminal in SES while debugging, but you may need to unset the following config in sdk_config.h:

// <q> NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED  - For each printed LF, function will add CR.
 

#ifndef NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED
#define NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 0
#endif