智能车HCS12 ECT PWM

FreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.TMFreescaleHCS12微控制器MC9S12DP2562005年8月FreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.TMEnhancedCaptureTimerModule增强型捕捉定时器模块TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide2ECT模块结构•一个16位向上带可编程预分频的主计数器.•一个16位的带可编程预分频的模数向下计数器•8个独立的定时器通道，每个通道具备输入捕捉和输出比较功能•4个8位脉冲累加器，也可设置成2个16位脉冲累加器.•通过对寄存器编程可以实现不同的功能TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide3定时器结构预分频选择PR[2:0]MClock1248163264128TCNT15...........................................0DATABUSPINRRRR1–计数器使能0–计数器禁止TENTSWAITSFRZTFFCATSCR1-定时器控制寄存器RST:00000000TCNTCLK.TENB0.......……...B7B8……..........B15R=Reserved$0006AddressOffset$0004,05$FFFE$FFFF$0000*******************TOF模块时钟计数器寄存器脉冲累加器计时器溢出时，对溢出标志位置位，如允许中断，则向CPU发出中断请求TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide4定时器，预分频，计数器寄存器:1.TCNT16位自由运行/模计数器B15............................................................................................................................…B0RST:0........................................................................................................................0AddressOffset$0004,$00051–定时器溢出中断使能0–定时器中断禁止$000D3.TSCR2RST:000000001–定时器由OC7比较符合时复位0–定时器自由运行TCRE-允许使用PWM功能B7....................................................................................B0TOI000TCREPR2PR1PR02.TFLG2定时器溢出标志位，写‘1’清零TOF0000000B7......................................................................B0RST:00000000$000F标志寄存器除以1248163264128000011110101010100110011PR2PR1PR0预分频系数选择TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide5定时器编程步骤用途：产生周期中断•初始化1.设定预分频系数2.定时器溢出中断使能3.定时器使能•中断函数1.清标志位2.用户自己的代码voidECT_Init(void){TSCR2_PR=7;//prescalefactoris8,busclock/128=8Mhz/8TSCR2_TOI=1;//timeroverflowinterruptenableTSCR1_TEN=1;//timerenable}#pragmaCODE_SEGNON_BANKED#pragmaTRAP_PROCvoidInt_TimerOverFlow(void){TFLG2_TOF=1;//cleartimeroverflowflag//用户自己的代码…………….}#pragmaCODE_SEGDEFAULT在PRM文件中，加入VECTORADDRESS0xFFDEInt_TimerOverFlowTMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide6输出比较功能16位自由运行计数器16位输出比较寄存器比如：0x5678软件可以修改引脚控制逻辑中断请求OCxF状态标志位置位，当比较发生时（值相等时）OCxI中断屏蔽(通过软件使能)•共有8个输出比较通道•每个通道有自己的向量表和控制寄存器•在特定的时刻输出一个信号当比较寄存器的值和计数器的值相等时，采取行动比如：当TCNT=0x5678TCNTTOCxPinOCx比较比较器相等置位OROR清零翻转TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide7输出比较寄存器C7FC6FC5FC4FC3FC2FC1FC0FOM7OL7OM6OL6OM5OL5OM4OL41.TC7–TC02.TFLG13.TIE4.TCTL1比较/捕捉标志位写‘1’清除中断状态标志位比较/捕捉屏蔽位0=屏蔽中断请求1=中断请求允许OMXOLXActiononOCx00110101NoActionOCxToggleOCxDriveOCxLODriveOCxHI输出模式和输出电平(O7–OC0)B6B5B4B3B7B2B1B05.TCTL2B6B5B4B3B7B2B1B0RST:00000000$0008RST:00000000RST:00000000RST:00000000$000C$000E$0009AddressOffset$0010-$0011--$001E-$001F16位捕捉/比较寄存器(TC7)16位捕捉/比较寄存器(TC0)--C7FC6FC5FC4FC3FC2FC1FC0FB6B5B4B3B7B2B1B0OM3OL3OM2OL2OM1OL1OM0OL0B6B5B4B3B7B2B1B0FOC7FOC6FOC5FOC4FOC3FOC2FOC1FOC06.CFORCB7B6B5B4B3B2B1B0RST:00000000$0001TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide8输出比较,OC7-OC0中断:•清除中断，对TFLG1其中的OCxF写’1’•不要使用位操作•使用OC7-OC0向量表复位条件：•自由运行计数器(TCNT)被初始化为$0000，并且被禁止•输出比较寄存器被初始化为$0000•捕捉/比较引脚与比较功能断开•中断被禁止•标志位被清零•强制比较位被清零•TMFreescaleSemiconductorConfidentialandProprietaryInformation.Freescale™andtheFreescalelogoaretrademarksofFreescaleSemiconductor,Inc.Allotherproductorservicenamesarethepropertyoftheirrespectiveowners.©FreescaleSemiconductor,Inc.2005.Slide9输出比较,通道7OC7(1of2)用途:1、多个输出比较引脚的控制2、通过2个输出比较来控制1个引脚，可以输出短脉冲在每个时钟周期内，输出比较寄存器7和自由运行的计数器进行比较如果它们的值相等，则：1、中断标志位被置12、输出引脚OC7-OC0的状态被改变或/和产生