NICLA SENSE ME (nRF52832) UART RX Issue

RE: NICLA SENSE ME (nRF52832) UART RX Issue

Vidar Berg — Mon, 08 Aug 2022 11:39:55 GMT

Thanks for confirming that it fixed the problem. I'm glad to hear that it works now.

Regards,

Vidar

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Mon, 08 Aug 2022 11:28:51 GMT

Hi Vidar,

This fix is working. Configured NFCT pins as GPIOs, and Explicitly pulling up RX pin in the application after UART init.

Thank you so much for your help and support. Really appreciate it.

Regards

RE: NICLA SENSE ME (nRF52832) UART RX Issue

Vidar Berg — Mon, 08 Aug 2022 09:12:11 GMT

Hi Ijaz,

I noticed now that UART RX is assigned to P0.9, same pin that is used as the antenna input for NFC by default (Pin assignments, Pin configuration).

To allow this pin to be used as a regular GPIO, you need to build your project with the CONFIG_NFCT_PINS_AS_GPIOS flag.

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Mon, 08 Aug 2022 08:58:39 GMT

Hi Vidar,

Please see the terminal screenshot for your reference. COMM. error triggered twice by default (Print from event handler), i have not even tried to send any data.

Regards

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Mon, 08 Aug 2022 08:34:54 GMT

Are you sending lots of data when the assert occurs?

==> No. I am just trying to send a char from PC terminal. In TX just printing some sample prints to make sure tx us working fine.

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Mon, 08 Aug 2022 08:32:39 GMT

Hi Vidar,

I tried the above snippet as you mentioned. TX also not working. Some junk value getting printed sometimes. I am also doing the following init with respect to clock. Just for your reference.

/* Initialize the low frequency clock */
nrf_drv_clock_init()

inrf_drv_power_init(NULL)

/* Request the clock to not to generate events */
nrf_drv_clock_lfclk_request(NULL);
nrf_drv_clock_hfclk_request(NULL);

while (!nrf_drv_clock_lfclk_is_running() && !nrf_drv_clock_hfclk_is_running())
;

Regards,

Ijaz

RE: NICLA SENSE ME (nRF52832) UART RX Issue

Vidar Berg — Mon, 08 Aug 2022 08:21:32 GMT

Hi Ijas,

Good point, I forgot that TX was working. This indicates that the baudrate accuracy is good enough for the receiver, at least.

As a test, you can try to use the crystal oscillator to increase the baudrate accuracy on the nRF side. You can do so by running the following snippet at the start of main():

    NRF_CLOCK->TASKS_HFCLKSTART = 1;
    while(NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);

Are you sending lots of data when the assert occurs?

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Mon, 08 Aug 2022 08:16:02 GMT

Hi Vidar,

I shall check and update you. Since TX is working for both 9600 and 115200, is there any chance of baud rate issue. I have verified TX with putty and hterm.

Rx test point is available in the board. Could you please let me know how to validate the baudrate / activity on RX pin using a logic analyzer.

Regards,

Ijas

RE: NICLA SENSE ME (nRF52832) UART RX Issue

Vidar Berg — Mon, 08 Aug 2022 07:29:31 GMT

Hi ljas,

The problem does not seem to be caused by a floating input since APP_UART_COMMUNICATION_ERROR still gets raised after you have enabled pull-up on RX, but rather that the transmitter is sending an "invalid" packet to your device. If you have a logic analyzer or scope available, you could try to probe the bus lines to verify that the baudrates match on both sides.

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Mon, 08 Aug 2022 04:33:10 GMT

Hi Vidhar,

There is an update, I would like to share.

I have tried configuring the RX pin as "nrf_gpio_cfg_input(RX_PIN_NUMBER_NICLA,NRF_GPIO_PIN_PULLUP)" after calling APP_UART_FIFO_INIT.

Also tried modifying UART driver portion that configures RX pin (Fun: apply_config, File: nrfx_uart.c).

The reception is not happening. Also observed that, in event handler "APP_UART_COMMUNICATION_ERROR" is getting triggered.

For testing RX functionality I tried the following methods.

case APP_UART_DATA_READY:
//APP_ERROR_CHECK(nrf_drv_uart_rx((uint8_t *)rx_data, LENGHT_RX));

printf("\r\nUART DATA Ready.\r\n");
while(app_uart_get(&gb) != NRF_SUCCESS);

if (gb == 'q' || gb == 'Q')
{
printf(" \r\nExit!\r\n");
}
break;

======================================================

while (true)
{
uint8_t cr;
while (app_uart_get(&cr) != NRF_SUCCESS);
while (app_uart_put(cr) != NRF_SUCCESS);

if (cr == 'q' || cr == 'Q')
{
printf(" \r\nExit!\r\n");

while (true)
{
// Do nothing.
}

}
}

==========================================================

Please let me know what am I missing. Thank you.

Regards,

Ijas

RE: NICLA SENSE ME (nRF52832) UART RX Issue

ijf1 — Fri, 05 Aug 2022 13:17:53 GMT

Hi Vidar,

The program runs with RX enabled on commenting "APP_ERROR_HANDLER(p_event->data.error_communication);".

But RX does not seem to work.

I tried the below code to receive from PC terminal.

while (true)
{
uint8_t cr;
while (app_uart_get(&cr) != NRF_SUCCESS);
while (app_uart_put(cr) != NRF_SUCCESS);

if (cr == 'q' || cr == 'Q')
{
printf(" \r\nExit!\r\n");

while (true)
{
// Do nothing.
}
}
}

Also can you please clarify the expected UART RX pin state. Has it to be handled in the schematics ? I tried configuring the RX pin as input and pulldown before UART init. It does not work.

Regards

Ijaz

RE: NICLA SENSE ME (nRF52832) UART RX Issue

Vidar Berg — Fri, 05 Aug 2022 10:40:04 GMT

Hello,

Please try to comment the "APP_ERROR_HANDLER(p_event->data.error_communication);" line in uart_error_handle() and see if that allows you to run the program with RX enabled.

The APP_UART_COMMUNICATION_ERROR is often triggered if the UART RX pin is left floating.

Best regards,

Vidar