17.8.3.2.1 Code
The following must be added to the user application:
- A sample buffer to send, number of entries to send and address of slave:
Number of times to try to send packet if it fails:#define DATA_LENGTH 10
static
uint8_t buffer[DATA_LENGTH] = {
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
};
#define SLAVE_ADDRESS 0x12
#define TIMEOUT 1000
- Globally accessible module structure:
struct
i2c_master_module i2c_master_instance;
- Function for setting up the module:
static
void
configure_i2c_master(
void
)
{
/* Initialize config structure and software module. */
struct
i2c_master_config config_i2c_master;
i2c_master_get_config_defaults(&config_i2c_master);
/* Change buffer timeout to something longer. */
config_i2c_master.buffer_timeout = 10000;
/* Initialize and enable device with config. */
i2c_master_init(&i2c_master_instance, CONF_I2C_MASTER_MODULE, &config_i2c_master);
i2c_master_enable(&i2c_master_instance);
}
- Globally accessible DMA module structure:
struct
dma_resource example_resource;
- Globally transfer done flag:
static
volatile
bool
transfer_is_done =
false
;
- Globally accessible DMA transfer descriptor:
COMPILER_ALIGNED(16)
DmacDescriptor example_descriptor;
- Function for transfer done callback:
static
void
transfer_done(
struct
dma_resource*
const
resource )
{
UNUSED(resource);
transfer_is_done =
true
;
}
- Function for setting up the DMA resource:
static
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:
static
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.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);
dma_descriptor_create(descriptor, &descriptor_config);
}
- Add to user application main():
configure_i2c_master();
configure_dma_resource(&example_resource);
setup_dma_descriptor(&example_descriptor);
dma_add_descriptor(&example_resource, &example_descriptor);
dma_register_callback(&example_resource, transfer_done,
DMA_CALLBACK_TRANSFER_DONE);
dma_enable_callback(&example_resource, DMA_CALLBACK_TRANSFER_DONE);