Using pin 6 as GPIO in SPI functionality

RE: Using pin 6 as GPIO in SPI functionality

Simon — Tue, 19 Feb 2019 13:55:57 GMT

[quote user="noob_with_ucontrollers"]I was wondering, if I need the uart functionality, could I re-assign uart TX and RX pins somewhere in the project? Which file/settings should I look into to reassign these pins to sth else so I can both use pin 6 as gpio and use uart functions?[/quote]

The UART RX and TX pins are configured in the function uart_init() in main.c.

Regarding the second question, you should make a new thread and present your problem there. In that way, the threads will only include content related to the initial question, and it is easier and quicker for people to find answers to their questions.

Best regards,

Simon

RE: Using pin 6 as GPIO in SPI functionality

noob_with_ucontrollers — Sat, 16 Feb 2019 00:19:53 GMT

Thank you Simon FerresSimon. Deleting all calls to the uart functions and the NRF_LOG functions solves this problem.

I was wondering, if I need the uart functionality, could I re-assign uart TX and RX pins somewhere in the project? Which file/settings should I look into to reassign these pins to sth else so I can both use pin 6 as gpio and use uart functions?

Also, I am not sure if I am supposed to start a new thread/post for this but even though my pin 6 works fine and the SPI communication is working on my custom PCB device, the nus_data_send () function does not send the SPI data to the NRF_TOOLBOX app on my phone.... I've tried calling the nus_data_send() function in the NUS_DATA_HANDLER as well as in main () program and in the spi_event_handler but it doesn't send the data from the SPI instead it sends some random garbage values to the app.

This is how I call the nus_data_send(). I initialize data_array with values from the RX buf of SPI.

err_code1 = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
                        if ((err_code1 != NRF_ERROR_INVALID_STATE) &&
                            (err_code1 != NRF_ERROR_RESOURCES) &&
                            (err_code1 != NRF_ERROR_NOT_FOUND))
                        {
                            APP_ERROR_CHECK(err_code1);
                        }

RE: Using pin 6 as GPIO in SPI functionality

Simon — Thu, 14 Feb 2019 10:21:01 GMT

The reason advertising stops when you remove uart_init() is because printf() is called before advertising_start(). The function printf() uses the UART parameters to print the data, but since the parameters are never set, the programs hangs at printf() and never calls advertising_init(). If you want to use pin 6, then you won't be able to receive logging through the interface MCU and USB, since pin 6 is connected to the TX line. The solution is to comment out the printf() and the app_uart_put() functions as well.

Best regards,

Simon

RE: Using pin 6 as GPIO in SPI functionality

noob_with_ucontrollers — Tue, 12 Feb 2019 19:54:47 GMT

That makes sense. I commented out the uart_init() function in main and ran the program on my device. Pin 6 works fine (i.e. goes high and low according to program).
However, when I remove the uart_init() function, the device stops advertising. I didn't know the uart was important for the ble functionality? How do I remove the uart functions without disrupting the ble or nus functionality?

Thanks Simon!

RE: Using pin 6 as GPIO in SPI functionality

Simon — Tue, 12 Feb 2019 13:00:17 GMT

The reason you won't find the use of pin 6 in the sdk_config.h file is because it is declared somewhere else. The ble_app_uart example doesn't use the UART backend for logging, and as a consequence does not have any of the defines in the sdk_config.h file, and this solution doesn't help you.

However, the example uses the function app_uart_put(..), which is called directly from main, and through printf()-->app_uart_put() as well. The pins TX and RX pins are decided through the function APP_UART_FIFO_INIT(), which is called from main in the function uart_init(..).

Enough talk. Pin 6 is assigned as TX pin in the function uart_init(..) in main.c of the ble_app_uart example.

Best regards,

Simon