18.8.3.2.1 Code

Address to respond to:

#define SLAVE_ADDRESS 0x12

A sample buffer to send, number of entries to send and address of slave:

#define DATA_LENGTH 10
uint8_t read_buffer[DATA_LENGTH];

Globally accessible module structure:

struct i2c_slave_module i2c_slave_instance;

Function for setting up the module:

void configure_i2c_slave(void)
{
    /* Create and initialize config_i2c_slave structure */
    struct i2c_slave_config config_i2c_slave;
    i2c_slave_get_config_defaults(&config_i2c_slave);

    /* Change address and address_mode */
    config_i2c_slave.address        = SLAVE_ADDRESS;
    config_i2c_slave.address_mode   = I2C_SLAVE_ADDRESS_MODE_MASK;
    config_i2c_slave.buffer_timeout = 1000;

    /* Initialize and enable device with config_i2c_slave */
    i2c_slave_init(&i2c_slave_instance, CONF_I2C_SLAVE_MODULE, &config_i2c_slave);

    i2c_slave_enable(&i2c_slave_instance);
}

Globally accessible DMA module structure:

struct dma_resource i2c_dma_resource;

Globally accessible DMA transfer descriptor:

COMPILER_ALIGNED(16)
DmacDescriptor i2c_dma_descriptor;

Function for setting up the DMA resource:

void configure_dma_resource(struct dma_resource *resource)
{
    struct dma_resource_config config;

    dma_get_config_defaults(&config);

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

    dma_allocate(resource, &config);
}

Function for setting up the DMA transfer descriptor:

void setup_dma_descriptor(DmacDescriptor *descriptor)
{
    struct dma_descriptor_config descriptor_config;

    dma_descriptor_get_config_defaults(&descriptor_config);

    descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE;
    descriptor_config.src_increment_enable = false;
    descriptor_config.block_transfer_count = DATA_LENGTH;
    descriptor_config.destination_address = (uint32_t)read_buffer + DATA_LENGTH;
    descriptor_config.source_address =
            (uint32_t)(&i2c_slave_instance.hw->I2CS.DATA.reg);

    dma_descriptor_create(descriptor, &descriptor_config);
}

Add to user application main():

configure_i2c_slave();

configure_dma_resource(&i2c_dma_resource);
setup_dma_descriptor(&i2c_dma_descriptor);
dma_add_descriptor(&i2c_dma_resource, &i2c_dma_descriptor);