STM32F446 包括IO操作,SPI操作，内部定时器,ADC的DMA方式，DAC的DMA方式，UART的DMA方式,CAN的通用方式。适合STM32F4xx系统(STM32F446 includes IO operation, SPI operation, internal timer, DMA mode of ADC, DMA mode of DAC, DMA mode of UART, common mode of CAN. Suitable for STM32F4xx system)