Workflow

system_init();

configure_rtc();

1. 2.1.
   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. 2.2.
   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. 2.3.
   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. 2.4.
   Enable the RTC module, so that it may begin counting.

   rtc_count_enable(&rtc_instance);
   

configure_rtc_callbacks();

1. 3.1.
   Register overflow callback.

   rtc_count_register_callback(
           &rtc_instance, rtc_tamper_callback, RTC_COUNT_CALLBACK_TAMPER);
   

2. 3.2.
   Enable overflow callback.

   rtc_count_enable_callback(&rtc_instance, RTC_COUNT_CALLBACK_TAMPER);
   

1. 4.1.
   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. 4.2.
   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. 4.3.
   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. 4.4.
   Allocate a DMA resource with the configurations.

   dma_allocate(resource, &config);
   

5. 4.5.
   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. 4.6.
   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. 4.7.
   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. 4.8.
   Create the DMA transfer descriptor.

   dma_descriptor_create(descriptor, &descriptor_config);
   

9. 4.9.
   Add DMA descriptor to DMA resource.

   dma_add_descriptor(&example_resource, &example_descriptor);