50.5. PWM输出

50.5.1. 概述

pwm 工程主要演示了如何配置几种不同类型的pwm波形并通过MCU的引脚进行输出。

• 强制输出

• 边沿对齐PWM

• 中心对齐PWM

• 中心对齐互补PWM

• PWM故障保护

• 四路比较器输出（支持AND、XOR、CD等不同逻辑模式）

• PWM DAC输出

• 带抖动补偿的边沿对齐PWM

50.5.2. 配置

• 一个双通道示波器

• 安装串口终端，查看 板子信息 并配置串口终端参数

• PWM_P0和PWM_P1引脚 根据板子型号查看具体信息

50.5.3. 运行现象

• 上电后，通过示波器可依次观测到： - P0、P1输出高电平和低电平 - 占空比从0%到100%变化的边沿对齐PWM - 占空比从0%到100%变化的中心对齐PWM - 占空比从0%到100%变化的中心对齐互补PWM - 不同逻辑模式的四路比较器输出 - 占空比可变的PWM DAC输出 - 带抖动补偿的边沿对齐PWM

• 失效引脚给定高电平后，P0和P1引脚PWM输出低电平，失效引脚给定低电平后，P0和P1引脚PWM恢复正常

• 串口打印如下信息:

pwm example

>> Test force PWM output on P0 and P1
Output high
Output low

>> Generate edge aligned waveform
Two waveforms will be generated, PWM P0 is the target waveform
whose duty cycle will be updated from 0 - 100 and back to 0; PWM P1 is a reference

>> Generate central aligned waveform
Two waveforms will be generated, PWM P0 is the target waveform
whose duty cycle will be updated from 0 - 100 and back to 0; PWM P1 is a reference

>> Generate central aligned waveform in pair
Two waveforms will be generated in pair, PWM P0 and P1 are target
waveforms whose duty cycle will be updated from 0 - 100 and back to 0

>> Generate edge aligned jit waveform
Two waveforms will be generated, PWM P0 is the target waveform
whose duty cycle will be updated from 0 - 100 and back to 0; PWM P1 is a reference

>> Generate four cmp waveform
Two waveforms will be generated, PWM P0 is the target waveform
whose duty cycle will be updated from 0 - 100 and back to 0; PWM P1 is a reference

>> Generate pwm dac waveform
Two waveforms will be generated, PWM P0 is the target waveform
whose duty cycle will be updated from 0 - 100 and back to 0; PWM P1 is a reference

test done

Note

演示程序会依次输出每种PWM波形一次。如果需要再次观测波形，需要重新运行程序。