The STM32F405xx and STM32F407xx family is based on the high-performance ARM? Cortex?-M4 32-bit RISC core operating at a frequency of up to 168 MHz. The Cortex-M4 core features a Floating point unit （FPU） single precision which supports all ARM singleprecision data-processing instructions and data types. It also implements a full set of DSP instructions and a memory protection unit （MPU） which enhances application security. The Cortex-M4 core with FPU will be referred to as Cortex-M4F throughout this document. The STM32F405xx and STM32F407xx family incorporates high-speed embedded memories （Flash memory up to 1 Mbyte， up to 192 Kbytes of SRAM）， up to 4 Kbytes of backup SRAM， and an extensive range of enhanced I/Os and peripherals connected to two APB buses， three AHB buses and a 32-bit multi-AHB bus matrix. All devices offer three 12-bit ADCs， two DACs， a low-power RTC， twelve general-purpose 16-bit timers including two PWM timers for motor control， two general-purpose 32-bit timers. a true random number generator （RNG）。 They also feature standard and advanced communication interfaces.