详细介绍了ARM9的系统结构，存储器配置，DMA、ADC和触摸屏、中断控制器、I/O、PWM、UART等-Details on the ARM9 architecture, memory configuration, DMA, ADC and touch screen, interrupt controller, I/O, PWM, UART, etc.

通过PWM定时器延迟一秒，实现一个LED灯的明灭。实验中观察I/O口的值对LED灯的明灭的控制，学习I/O口的输入输出方式和设置，了解PWM的配置方式-Through the PWM timer to delay a second, the realization of a LED lamp at. I/O values for LED lamp light control experiment, learning I/O port input and output method and set

可以在STM32F407生成理想pwm波形，而且不用配置硬件环境，可以直接用，不用更改STM32板级设置，效果很好-PWM waveform can be generated in STM32F407 ideal, and need not to configure hardware environment, can use directly, need not modify the Settings of the STM32 board level, the effect is very go

通过对定时器3的通道3和通道4的配置来实现PWM的输出，并且可以通过调整占空比来实现对电机转速的控制。