[Atmel] SAML21走起3：CALLBACK回调方式UART

#include <asf.h>

struct usart_module usart_instance;

#define MAX_RX_BUFFER_LENGTH   15



volatile uint8_t rx_buffer[MAX_RX_BUFFER_LENGTH];









void configure_usart(void);

void usart_read_callback(struct usart_module *const usart_module);

void usart_write_callback(struct usart_module *const usart_module);

void configure_usart_callbacks(void);





void configure_usart(void)

{

        struct usart_config config_usart;

        usart_get_config_defaults(&config_usart);

        config_usart.baudrate    = 9600;

        config_usart.mux_setting = EDBG_CDC_SERCOM_MUX_SETTING;

        config_usart.pinmux_pad0 = EDBG_CDC_SERCOM_PINMUX_PAD0;

        config_usart.pinmux_pad1 = EDBG_CDC_SERCOM_PINMUX_PAD1;

        config_usart.pinmux_pad2 = EDBG_CDC_SERCOM_PINMUX_PAD2;

        config_usart.pinmux_pad3 = EDBG_CDC_SERCOM_PINMUX_PAD3;

        while (usart_init(&usart_instance,

        EDBG_CDC_MODULE, &config_usart) != STATUS_OK) {

        }

        usart_enable(&usart_instance);

}





int main (void)

{

        system_init();

        configure_usart();

        configure_usart_callbacks();

        

         system_interrupt_enable_global();

         uint8_t string[] = "Hello World!\r\n";

         usart_write_buffer_wait(&usart_instance, string, sizeof(string));

         while (true) {

                 usart_read_buffer_job(&usart_instance,

                 (uint8_t *)rx_buffer, MAX_RX_BUFFER_LENGTH);

         }



        

}







void usart_read_callback(struct usart_module *const usart_module)

{

        usart_write_buffer_job(&usart_instance,

        (uint8_t *)rx_buffer, MAX_RX_BUFFER_LENGTH);

}

void usart_write_callback(struct usart_module *const usart_module)

{

        port_pin_toggle_output_level(LED_0_PIN);

}

void configure_usart_callbacks(void)

{

        usart_register_callback(&usart_instance,

        usart_write_callback, USART_CALLBACK_BUFFER_TRANSMITTED);

        usart_register_callback(&usart_instance,

        usart_read_callback, USART_CALLBACK_BUFFER_RECEIVED);

        usart_enable_callback(&usart_instance, USART_CALLBACK_BUFFER_TRANSMITTED);

        usart_enable_callback(&usart_instance, USART_CALLBACK_BUFFER_RECEIVED);

}