DSP时钟

1） INTOSC1（10MHz） 
内部时钟源1（INTOSC1），此时钟提供给看门狗块模块，内核和CPU定时器2 。 
时钟频率默认为10MHz，可以通过INTOSCnTRIM寄存器修改频率。 
2） INTOSC2（10MHz） 
功能与INTOSC1是一样的。 
3） 外部晶体振荡器 
使用外部晶体振荡器给芯片提供时钟，晶振连接于X1/X2 脚。 
4） 外部时钟源 
如果不使用外部晶振作为时钟源，可以选择这种模式。时钟从外部时钟源的XCLKIN引脚输入生成。    下图可以看出SPI、SCI、I2C使用低速时钟，EPWM、ECAP、EQEP采用系统时钟、ADC采用高速时钟

步进驱动dsp2806

#define DSP28_CLKINDIV 0 #define DSP28_PLLCR 10 void InitSysCtrl(void) { DisableDog(); InitPll(DSP28_PLLCR, DSP28_CLKINDIV); InitPeripheralClocks(); } 选择外部20M晶振， 系统时钟SYSCLKOUT = ( OSCCLK x 10) / div = ( 20 x 10 ) / 2 = 100MHz

平车DSP28034

#define DSP28_DIVSEL 2 #define DSP28_PLLCR 12 void InitSysCtrl(void) { DisableDog(); IntOsc1Sel(); InitPll(DSP28_PLLCR,DSP28_DIVSEL); InitPeripheralClocks(); } 选择10MHz内部振荡器1作为时钟 SYSCLKOUT = ( 10 x 12 ) / 2 = 60MHz SYSCtrlRegs.LOSPCP.all = 0x0002 低速时钟 = 60Mhz / 4 = 15MHz #define PWMPRD 3000 EPwm2Regs.TBPRD = PWMPRD; // Period = 3001 TBCLK counts 20M HZ EPwm2Regs.TBPHS.all = 0; // Set Phase register to zero EPwm2Regs.TBCTR = 0; // clear TB counter EPwm2Regs.TBCTL.bit.CTRMODE = TB_COUNT_UPDOWN; EPwm2Regs.TBCTL.bit.PHSEN = TB_ENABLE; // Phase loading enabled EPwm2Regs.TBCTL.bit.PRDLD = TB_SHADOW; EPwm2Regs.TBCTL.bit.SYNCOSEL = TB_SYNC_IN; EPwm2Regs.TBCTL.bit.PHSDIR = TB_UP; //counts up after syn EPwm2Regs.TBCTL.bit.HSPCLKDIV = TB_DIV1; // TBCLK = SYSCLK EPwm2Regs.TBCTL.bit.CLKDIV = TB_DIV1; EPwm2Regs.CMPCTL.bit.SHDWAMODE = CC_SHADOW; EPwm2Regs.CMPCTL.bit.SHDWBMODE = CC_SHADOW; EPwm2Regs.CMPCTL.bit.LOADAMODE = CC_CTR_ZERO_PRD; // load on CTR = Zero EPwm2Regs.CMPCTL.bit.LOADBMODE = CC_CTR_ZERO_PRD; // load on CTR = Zero EPwm2Regs.CMPA.half.CMPA = 1000; // Compare A = 350 TBCLK counts EPwm2Regs.CMPB = 1500; // Compare B = 200 TBCLK counts EPwm2Regs.AQCTLA.bit.ZRO = AQ_CLEAR; EPwm2Regs.AQCTLA.bit.CAU = AQ_SET; EPwm2Regs.AQCTLA.bit.PRD = AQ_SET; EPwm2Regs.AQCTLA.bit.CAD = AQ_CLEAR; EPwm2Regs.AQCTLB.bit.ZRO = AQ_CLEAR; EPwm2Regs.AQCTLB.bit.CBU = AQ_SET; EPwm2Regs.AQCTLB.bit.PRD = AQ_SET; EPwm2Regs.AQCTLB.bit.CBD = AQ_CLEAR; EPwm2Regs.DBCTL.bit.OUT_MODE = DB_FULL_ENABLE; //全部输出打开死区控制 EPwm2Regs.DBCTL.bit.POLSEL = DB_ACTV_LOC; //A输出逻辑低有效 EPwm2Regs.DBCTL.bit.IN_MODE = DBA_ALL; //AQ输出A作为死区控制输入 EPwm2Regs.DBFED = PWM_DeadbandTime; //死区时间设定 EPwm2Regs.DBRED = PWM_DeadbandTime; EPwm2Regs.TZSEL.bit.OSHT2 = TZ_ENABLE; //TZ1 One Time Tripper Protect EPwm2Regs.TZCTL.bit.TZA = TZ_FORCE_HI; EPwm2Regs.TZCTL.bit.TZB = TZ_FORCE_HI; //Protect State is Forced to Low EPwm2Regs.TZEINT.bit.OST = TZ_DISABLE; //Enable TZ Int EPwm2Regs.TZCLR.all = 0x07; //Clear all int flag EPwm2Regs.ETSEL.bit.INTEN = 0; // Disable EPWM interrupt EPwm2Regs.ETSEL.bit.INTSEL = ET_CTR_ZERO; EPwm2Regs.ETPS.bit.INTPRD = ET_1ST; // Generate an interrupt on the first event EPwm2Regs.ETCLR.bit.INT = 1; // Clear spurious interrupt EPwm2Regs.ETSEL.bit.INTEN = 1; // Enable EPWM interrupt PWM采用系统时钟60MHz，周期3000，采用增减计数模式，在时基计数器值为0是产生中断。因为每6000计数产生一次中断。 中断的中期 = 1 / 60M *6000 = 0.0001(s) = 0.1 (ms) = 100 (us) PWM的中断内包含QF_tick();，并且每进入10次处理一次。 QF_tick周期为1ms。