API Classification
Initialization APIs
These APIs initialize/deinitialize peripherals and peripheral-specific public resources, including enabling/disabling Nested Vectored Interrupt Controller (NVIC) interrupts, initializing/deinitializing pull-up/pull-down and functionality multiplexing of GPIOs, initializing/deinitializing DMA channels, and registering/unregistering sleep management APIs. Example: app_adc_init and app_adc_deinit.
Functional APIs
Functional APIs (such as app_tim_start and app_tim_stop) are used to enable/disable a functionality.
Transmission APIs
Based on data transmission modes, these APIs are categorized into three groups: polling mode APIs, interrupt mode APIs, and DMA mode APIs, such as app_uart_transmit_sync, app_uart_transmit_async, and app_uart_dma_transmit_async. Apart from the APIs used for traditional transmission modes, APIs supporting special operations are designed for some peripherals.
Control APIs
Control APIs (such as app_pwm_config_channel) are used to configure parameters.
Getting-handle APIs
Getting-handle APIs (such as app_i2c_get_handle) are used to get the handle of a peripheral to distinguish between peripheral instances. In certain circumstances, users can call HAL APIs or obtain HAL parameters through getting-handle APIs.
