I'm sending data to the serial port in two ways:
First, if I use a terminal emulator and send a character at a time, app_uart_get returns NRF_SUCCESS for each character. The UART error handler is also called once for each character as it goes on the fifo.
Second, if I send a 14-character string using using the "send file" feature of the terminal emulator, app_uart_get only returns NRF_SUCCESS for some of the characters. Others appear to get dropped. I can still see the UART error handler called 14 times as the characters come in, so I know they all arrived. But app_uart_get only returns NRF_SUCCESS 4 or 5 times.
Why would the UART/fifo drop characters that come in without a pause in between?
Here are some code snippets. I'm using the Segger RTT to implement printf.
#define UART_TX_BUF_SIZE 256 /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 256 /**< UART RX buffer size. */
void uart_error_handle(app_uart_evt_t * p_event)
{
printf("UART Error handler.\r\n");
}
const app_uart_comm_params_t comm_params = {
RX_PIN_NUMBER,
TX_PIN_NUMBER,
RTS_PIN_NUMBER,
CTS_PIN_NUMBER,
UART_HWFC,
false,
#if defined (UART_PRESENT)
NRF_UART_BAUDRATE_115200
#else
NRF_UARTE_BAUDRATE_115200
#endif
};
APP_UART_FIFO_INIT(&comm_params,
UART_RX_BUF_SIZE,
UART_TX_BUF_SIZE,
uart_error_handle,
APP_IRQ_PRIORITY_LOWEST,
err_code);
APP_ERROR_CHECK(err_code);
printf("UART test started.\r\n");
char_cnt = 0;
uint32_t uart_status;
while (true) {
uart_status = app_uart_get(&(JSON_char_buff[char_cnt]));
switch( uart_status ) {
case NRF_SUCCESS:
printf("NRF_SUCCESS\r\n");
char_cnt++;
continue;
case NRF_ERROR_NOT_FOUND:
// printf("NRF_ERROR_NOT_FOUND\r\n");
continue;
default:
printf("Unexpected status = 0x%x\r\n", uart_status );
continue;
}
}
