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ID:40526702
大小:777.00 KB
页数:22页
时间:2019-08-04
《Chapter 13 PWM》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、Chapter13Pulse-WidthModulator(S12PWM8B8CV1)中心对齐输出模式和4个可用的时钟源该PWM模块有8个独立控制中心和左对齐输出的通道。独立控制周期、占空比、计数器。ThePWMdefinitionisbasedontheHC12PWMdefinitions.ItcontainsthebasicfeaturesfromtheHC11withsomeoftheenhancementsincorporatedontheHC12:centeralignedoutputmodeandfouravailableclocksourc
2、es.ThePWMmodulehaseightchannelswithindependentcontrolofleftandcenteralignedoutputsoneachchannel.Eachoftheeightchannelshasaprogrammableperiodanddutycycleaswellasadedicatedcounter.Aflexibleclockselectschemeallowsatotaloffourdifferentclocksourcestobeusedwiththecounters.Eachofthemodu
3、latorscancreateindependentcontinuouswaveformswithsoftware-selectabledutyratesfrom0%to100%.ThePWMoutputscanbeprogrammedasleftalignedoutputsorcenteralignedoutputs.13.1.1Features周期和占空比双缓冲在有效周期的末尾或通道被禁用,更改才会有效(PWM计数器归零)8个8位或4个16位PWM通道Fourclocksources(A,B,SA,andSB)provideforawiderange
4、offrequencies4个时钟源(A,B,SA和SB)提供了广泛的频率紧急关闭ThePWMblockincludesthesedistinctivefeatures:•EightindependentPWMchannelswithprogrammableperiodanddutycycle•DedicatedcounterforeachPWMchannel•ProgrammablePWMenable/disableforeachchannel•SoftwareselectionofPWMdutypulsepolarityforeachchannel•
5、Periodanddutycyclearedoublebuffered.Changetakeseffectwhentheendoftheeffectiveperiodisreached(PWMcounterreacheszero)orwhenthechannelisdisabled.•Programmablecenterorleftalignedoutputsonindividualchannels•Eight8-bitchannelorfour16-bitchannelPWMresolution•Fourclocksources(A,B,SA,andS
6、B)provideforawiderangeoffrequencies•Programmableclockselectlogic•Emergencyshutdown13.1.2运行模式可编程禁止时钟进入分频器,以进入低功耗的等待模式。Freeze模式中有一个软件可编程选项禁止时钟输入分频器。这对仿真是有益的Thereisasoftwareprogrammableoptionforlowpowerconsumptioninwaitmodethatdisablestheinputclocktotheprescaler.Infreezemodethereisa
7、softwareprogrammableoptiontodisabletheinputclocktotheprescaler.Thisisusefulforemulation.13.2外部信号描述 13.2ExternalSignalDescriptionThePWMmodulehasatotalof8externalpins.该PWM模块共有8外部引脚。13.2.1PWM7—PWMChannel7ThispinservesaswaveformoutputofPWMchannel7andPWM通道7作为输入的紧急关断功能13.2.1PWM7—PWMCha
8、nnel7ThispinservesaswaveformoutputofPWMc
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