esp32-s2_dfu/doxygen/started_demo.md

Demos

For simplicity and user's convenience, there are only 2 basic application demos which are Device and Host respectively. Each application demo, however, has a few projects, each for its supported RTOS. For instance, in addition to the src folder, you will also find in the /demo/device

• device_os_none for no RTOS
• device_freertos for freeRTOS
• device_cmsis_rtx for ARM CMSIS with RTX implemenation

To be able to have the same application code running across RTOSes, the application make use of the "internal" OSAL layer. Thus this makes the application code a bit weird and over-complicated than it should be in some (many) cases. This is absolutely not necessary in product development. User can just use the native API function of supported RTOS or a state machine or blocking wait in case of none OS. For example, instead of the blinking task in application

OSAL_TASK_FUNCTION( led_blinking_task , p_task_para)
{
  OSAL_TASK_LOOP_BEGIN

  static uint32_t led_on_mask = 0;

  osal_task_delay(led_blink_interval_ms);

  board_leds(led_on_mask, 1 - led_on_mask);
  led_on_mask = 1 - led_on_mask; // toggle

  OSAL_TASK_LOOP_END
}

can be written in FreeRTOS's native API

void led_blinking_task( void * p_task_para )
{
  while(1)
  {
    static uint32_t led_on_mask = 0;

    // FreeRTOS API's vTaskDelay is used in place of osal_task_delay. Note it takes input parameter in tick
    vTaskDelay( (led_blink_interval_ms * CFG_TUSB_TICKS_HZ) / 1000);

    board_leds(led_on_mask, 1 - led_on_mask);
    led_on_mask = 1 - led_on_mask; // toggle
  }
}