Configuration

The first step in using uart is to configure and bring up the interface. The uart hal provides a configuration structure with the standard uart options. This structure should be filled out according to the project's uart configuration and then it may be used to initialize the interface in use.

KUARTConf conf = {
    .baud_rate = 115200,
    .word_len = K_WORD_LEN_8BIT,
    .stop_bits = K_STOP_BITS_1,
    .parity = K_PARITY_NONE,
    .rx_queue_len = 32,
    .tx_queue_len = 32,
};
k_uart_init(K_UART1, &conf);

Another option for configuration is to use our uart defaults. The k_uart_conf_defaults function will give you an already filled out configuration struct with the standard uart parameters (8 bit words, 1 stop bit, no parity). The only thing that needs to be specified is the interface in use.

KUARTConf conf = k_uart_conf_defaults();

k_uart_init(K_UART1, &conf);

Reading

Reading from uart is a pretty simple operation, a buffer and length is passed in. The buffer is filled and the number of characters read are passed back.

char buffer[100];
int num_read = 0;
num_read = k_uart_read(K_UART1, buffer, 10);

Writing

Writing to uart is also a simple operation, a buffer and length are passed in. The buffer is read from and the number of characters written are passed back.

char buffer[20];
int num_written = 0;
num_written = k_uart_write(K_UART1, buffer, 10);

API Docs

More detailed information on the HAL's uart functions and parameters can be found here - UART