Question about uart transfer buffer

[Jinyue Zhu]

So, I am developing an application where I will use uart to transmit some data from the PC to the nrf board. The issue is that the data I am transferring is quite large (64KB). I have written a code that would work in terms of communication, but I seriously suspect that not all data has been transmitted. Please see the attached as an example:

#define UART_TX_BUF_SIZE 256 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 256 /**< UART RX buffer size. */

// allocate space for the binary data
char bin_data[65536];

// function that handles receiving message from PC: as noted, I will basically pass my bin_data to the below function for getting data from the PC

bool receiveMessage(char * buffer, int start_index, bool cmd_flag) {

    while (app_uart_get(&cr) != NRF_SUCCESS);
    buffer[start_index] = cr;

    . ..

}

I am wondering what's the solution to receive full 65536 bytes from the PC? I have tested my code such that I know the message are all correct when they are less than the buffer size.

Thanks,

Jinyue

[Jinyue Zhu]

As a follow up, the baudrate I am using is 115200. On the PC end, the pyserial library is used to communicate with nRF through uart. Specifically, I am loading the data as a byte array (of size 64KB) and that gets send through uart by the function pyserial.write().

I am wondering what's the maximum buffer size allowed for Rx and Tx. Or should I slow down the baud rate? For now, it seems like when I am transmitting large sized data, the board cannot handle them in time and thus data were lost in the process. Thanks

[Simonr]

The only thing limiting the buffer sizes are the available RAM in your device, but usually 256 is sufficient for both TX and RX buffers. You say that you have a suspicion that some data is lost, are you not able to see what you send and receive and make sure that these match in content and size?

Best regards,

Simon