17.8.3.2.2 Workflow

configure_i2c_master();

1. Create and initialize configuration structure.

   struct i2c_master_config config_i2c_master;
   i2c_master_get_config_defaults(&config_i2c_master);
   

2. Change settings in the configuration.

   config_i2c_master.buffer_timeout = 10000;
   

3. Initialize the module with the set configurations.

   i2c_master_init(&i2c_master_instance, CONF_I2C_MASTER_MODULE, &config_i2c_master);
   

4. Enable the module.

   i2c_master_enable(&i2c_master_instance);
   

1. Create a DMA resource configuration structure, which can be filled out to adjust the configuration of a single DMA transfer.

   struct dma_resource_config config;
   

2. Initialize the DMA resource configuration struct with the module's default values.

   dma_get_config_defaults(&config);
   

   Note: This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings.
3. Set extra configurations for the DMA resource. It is using peripheral trigger. SERCOM TX trigger causes a transaction transfer in this example.

   config.peripheral_trigger = CONF_I2C_DMA_TRIGGER;
   config.trigger_action = DMA_TRIGGER_ACTON_BEAT;
   

4. Allocate a DMA resource with the configurations.

   dma_allocate(resource, &config);
   

5. Create a DMA transfer descriptor configuration structure, which can be filled out to adjust the configuration of a single DMA transfer.

   struct dma_descriptor_config descriptor_config;
   

6. Initialize the DMA transfer descriptor configuration struct with the module's default values.

   dma_descriptor_get_config_defaults(&descriptor_config);
   

   Note: This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings.
7. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address.

   descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE;
   descriptor_config.dst_increment_enable = false;
   descriptor_config.block_transfer_count = DATA_LENGTH;
   descriptor_config.source_address = (uint32_t)buffer + DATA_LENGTH;
   descriptor_config.destination_address =
           (uint32_t)(&i2c_master_instance.hw->I2CM.DATA.reg);
   

8. Create the DMA transfer descriptor.

   dma_descriptor_create(descriptor, &descriptor_config);