Configure DMA

  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);
config.peripheral_trigger = M2M_DMAC_TRIGGER_ID;
    Note: This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings.
  3. Allocate a DMA resource with the configurations. 
    dma_allocate(resource, &config);
  4. 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;
  5. 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.
  6. Set the specific parameters for a DMA transfer with transfer size, source address, and destination address. 
    descriptor_config.block_transfer_count = TRANSFER_SIZE;
descriptor_config.source_address = (uint32_t)source_memory + TRANSFER_SIZE;
descriptor_config.destination_address =
        (uint32_t)destination_memory + TRANSFER_SIZE;
  7. Create the DMA transfer descriptor. 
    dma_descriptor_create(descriptor, &descriptor_config);
  8. Add the DMA transfer descriptor to the allocated DMA resource. 
    dma_add_descriptor(&example_resource, &example_descriptor);
  9. Register a callback to indicate transfer status. 
    dma_register_callback(&example_resource, transfer_done,
        DMA_CALLBACK_TRANSFER_DONE);
  10. The transfer done flag is set in the registered callback function. 
    void transfer_done(struct dma_resource* const resource )
{
    UNUSED(resource);

    transfer_is_done = true;
}