14.10.3.1.3 Workflow

system_init();

configure_rtc();

1. Create a RTC configuration structure to hold the desired RTC driver settings and fill it with the configuration values.

   struct rtc_count_config config_rtc_count;
   rtc_count_get_config_defaults(&config_rtc_count);
   config_rtc_count.prescaler = RTC_COUNT_PRESCALER_DIV_1;
   rtc_count_init(&rtc_instance, RTC, &config_rtc_count);
   

   Note: This should always be performed before using the configuration struct to ensure that all values are initialized to known default settings.
2. Initialize the RTC module.

   struct rtc_count_config config_rtc_count;
   rtc_count_get_config_defaults(&config_rtc_count);
   config_rtc_count.prescaler = RTC_COUNT_PRESCALER_DIV_1;
   rtc_count_init(&rtc_instance, RTC, &config_rtc_count);
   

3. Create a RTC tamper configuration structure and fill it with the configuration values.

   struct rtc_tamper_config config_rtc_tamper;
   rtc_tamper_get_config_defaults(&config_rtc_tamper);
   config_rtc_tamper.dma_tamper_enable = true;
   config_rtc_tamper.in_cfg[0].level = RTC_TAMPER_LEVEL_RISING;
   config_rtc_tamper.in_cfg[0].action = RTC_TAMPER_INPUT_ACTION_CAPTURE;
   rtc_tamper_set_config(&rtc_instance, &config_rtc_tamper);
   

4. Enable the RTC module, so that it may begin counting.

   rtc_count_enable(&rtc_instance);
   

configure_rtc_callbacks();

1. Register overflow callback.

   rtc_count_register_callback(
           &rtc_instance, rtc_tamper_callback, RTC_COUNT_CALLBACK_TAMPER);
   

2. Enable overflow callback.

   rtc_count_enable_callback(&rtc_instance, RTC_COUNT_CALLBACK_TAMPER);
   

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. ADC_DMAC_ID_RESRDY trigger causes a beat transfer in this example.

   config.peripheral_trigger = RTC_DMAC_ID_TIMESTAMP;
   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_WORD;
   descriptor_config.dst_increment_enable = false;
   descriptor_config.src_increment_enable = false;
   descriptor_config.block_transfer_count = 1;
   descriptor_config.source_address = (uint32_t)(&rtc_instance.hw->MODE0.TIMESTAMP.reg);
   descriptor_config.destination_address = (uint32_t)(buffer_rtc_tamper);
   descriptor_config.next_descriptor_address = (uint32_t)descriptor;
   

8. Create the DMA transfer descriptor.

   dma_descriptor_create(descriptor, &descriptor_config);
   

9. Add DMA descriptor to DMA resource.

   dma_add_descriptor(&example_resource, &example_descriptor);