28335的AD采样频率设置问题

只看该作者 · 2016-6-26 23:07

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？