在TI提供的controlsuite中:
   EALLOW;
   #if (CPU_FRQ_150MHZ)     // Default - 150 MHz SYSCLKOUT
     #define ADC_MODCLK 0x3 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)   = 25.0 MHz
   #endif
   #if (CPU_FRQ_100MHZ)
     #define ADC_MODCLK 0x2 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 100/(2*2)   = 25.0 MHz
   #endif
   EDIS;

// Assumes ePWM1 clock is already enabled in InitSysCtrl();
   EPwm1Regs.ETSEL.bit.SOCAEN = 1;        // Enable SOC on A group
   EPwm1Regs.ETSEL.bit.SOCASEL = 4;       // Select SOC from from CPMA on upcount
   EPwm1Regs.ETPS.bit.SOCAPRD = 1;        // Generate pulse on 1st event
   EPwm1Regs.CMPA.half.CMPA = 0x0080;          // Set compare A value
   EPwm1Regs.TBPRD = 0xFFFF;              // Set period for ePWM1
   EPwm1Regs.TBCTL.bit.CTRMODE = 0;                  // count up and start
修改EPwm1Regs.TBPRD = 0xFFFF;这部分应该就是设置ADC频率了吧？
还有28335的晶振是30MHz，这里有用到吗？为什么？