RE: How to handle UART data? (nRF52832)

kishorsherolla — Thu, 07 Jan 2021 12:29:52 GMT

hello edvin ,

i am kishor new to this nrf52 module , actually iam implementing the code for gps master and slave clock , i want to send total gprmc packet after receiving the master ble to slave ble .. i am usng the sample code ble_app_uart(), in that rx buffer sige having the only one byte sholu i chage that bugger size, and can u suggest the little code

RE: How to handle UART data? (nRF52832)

Ferrell — Thu, 19 Jul 2018 04:35:38 GMT

Wow!!! I understood and it works perfect !!

Thank you for very detailed explanation and the code!

RE: How to handle UART data? (nRF52832)

Edvin — Wed, 18 Jul 2018 15:49:22 GMT

Hello,

You are on the right track. You should use the uart_event_handle() function.

Originally it works this way:

It is called every time the function gets called every time the nRF receives a byte/char on the UART. It stores that character in an array, data_array[], and checks if the array is full, or if the last char was '\n'. If it was, it will send the array on the BLE link.

I notice that $GPRMC is the only sequence startin with '$', and 'R' is the 4th char.

You will have to test and verify that this is working yourself, but I may give you some hints to get started.

Since you only are looking for strings starting with $, you can do something like:

        case APP_UART_DATA_READY:
      
            UNUSED_VARIABLE(app_uart_get(&b[index]));
            index++;
            if (data_array[0] != '$')
            {
                index = 0;
            }

This way, you will not start to store data until you get a '$'.

Then, when index reaches 3, you can check for an 'R':

        case APP_UART_DATA_READY:
      
            UNUSED_VARIABLE(app_uart_get(&b[index]));
            index++;
            if (data_array[0] != '$')
            {
                index = 0;
                break;
            }
            if ((index-1 >= 3) && (data_array[3] != 'R'))
            {
                index = 0;
                break;
            }

If the code passes this point, it will write to the data_array only when it starts with $GPRMC (or actually $**R), and you can continue to collect the data from the UART.

if you only want to do it every third second, you can either use a timer to set a variable that you also check before collecting data, or you can set a counter to only collect the data every third time you get a message starting with $GPRMC.

Did this make any sense, or was it only confusing?

Best regards,

Edvin