19.8.3.2 Workflow

system_init();

configure_spi_master();

1. Create configuration struct.

   struct spi_config config_spi_master;
   

2. Create peripheral slave configuration struct.

   struct spi_slave_inst_config slave_dev_config;
   

3. Get default peripheral slave configuration.

   spi_slave_inst_get_config_defaults(&slave_dev_config);
   

4. Set Slave Select pin.

   slave_dev_config.ss_pin = SLAVE_SELECT_PIN;
   

5. Initialize peripheral slave software instance with configuration.

   spi_attach_slave(&slave, &slave_dev_config);
   

6. Get default configuration to edit.

   spi_get_config_defaults(&config_spi_master);
   

7. Set MUX setting E.

   config_spi_master.mux_setting = EXT1_SPI_SERCOM_MUX_SETTING;
   

8. Set pinmux for pad 0 (data in MISO).

   config_spi_master.pinmux_pad0 = EXT1_SPI_SERCOM_PINMUX_PAD0;
   

9. Set pinmux for pad 1 as unused, so the pin can be used for other purposes.

   config_spi_master.pinmux_pad1 = PINMUX_UNUSED;
   

10. Set pinmux for pad 2 (data out MOSI).

    config_spi_master.pinmux_pad2 = EXT1_SPI_SERCOM_PINMUX_PAD2;
    

11. Set pinmux for pad 3 (SCK).

    config_spi_master.pinmux_pad3 = EXT1_SPI_SERCOM_PINMUX_PAD3;
    

12. Initialize SPI module with configuration.

    spi_init(&spi_master_instance, EXT1_SPI_MODULE, &config_spi_master);
    

13. Enable SPI module.

    spi_enable(&spi_master_instance);
    

configure_spi_master_callbacks();

1. Register callback function for buffer transmitted.

   spi_register_callback(&spi_master_instance, callback_spi_master,
           SPI_CALLBACK_BUFFER_TRANSCEIVED);
   

2. Enable callback for buffer transmitted.

   spi_enable_callback(&spi_master_instance, SPI_CALLBACK_BUFFER_TRANSCEIVED);