DSP28335的eCAP模块捕获脉冲问题

只看该作者 · 2019-7-31 19:12

本帖最后由闵大于 2019-7-31 19:39 编辑

DSP28335的eCAP模块捕获脉冲问题

   各位大佬，小弟想请教一个问题。DSP28335的eCAP模块捕获脉冲上升沿计数结果和脉冲本身幅值有关吗？
   今天学习eCAP模块并烧写例程代码到开发板上，用函数信号发生器发出一路频率为10KHz，Vpp=1V占空比0.5的方波。通过watchwindow观测T1值，发现T1在2200上下波动。然后把方波幅值改为Vpp=3.0V时发现T1值接近15000。截图和源代码如下。
   T1=150MHz/10KHz。
                                       TMS320F28335工作频率=150MHz
                                       所测信号频率=10KHz
图一：Vpp=1V 图二：Vpp=3V

图1（上图）

图2（上图）

#include "DSP2833x_Device.h" // DSP2833x Headerfile Include File

#include"DSP2833x_Examples.h" //DSP2833x Examples Include File

Uint16 *ExRamStart = (Uint16 *)0x100000;

Uint32t1=0,t2=0,t3=0,t4=0,T1=0,T2=0,t5,t6,t7,t8,T3,T4;

interrupt void ISRCap1(void);

interrupt void ISRCap2(void);

Uint16 i;

void main(void)

{

InitSysCtrl();

InitXintf16Gpio(); //zq

DINT;

InitPieCtrl();

// Disable CPU interrupts and clear all CPUinterrupt flags:

IER = 0x0000;

IFR = 0x0000;

InitPieVectTable();

EALLOW; // This is needed towrite to EALLOW protected registers

PieVectTable. ECAP1_INT = &ISRCap1;

PieVectTable. ECAP2_INT = &ISRCap2;

EDIS; // This is needed todisable write to EALLOW protected registers

InitCapl();

IER |= M_INT4;

// Enable TINT0 in the PIE: Group 4interrupt1

PieCtrlRegs.PIEIER4.bit.INTx1 = 1;

PieCtrlRegs.PIEIER4.bit.INTx2 = 1;

// Enable global Interrupts and higherpriority real-time debug events:

EINT; // Enable Global interruptINTM

ERTM; // Enable Global realtimeinterrupt DBGM

i= 0;

for(; ;)

{

}

interrupt void ISRCap1(void)

{

//Acknowledge this interrupt to receive more interrupts from group 1

PieCtrlRegs.PIEACK.all = PIEACK_GROUP4;

ECap1Regs.ECCLR.all=0xFFFF;//clare all flag

t1=ECap1Regs.CAP1;

t2=ECap1Regs.CAP2;

t3=ECap1Regs.CAP3;

t4= ECap1Regs.CAP4;

T1=t2-t1;T2=t4-t3;

}

interrupt void ISRCap2(void)

{

//Acknowledge this interrupt to receive more interrupts from group 1

PieCtrlRegs.PIEACK.all = PIEACK_GROUP4;

ECap2Regs.ECCLR.all=0xFFFF;//clare all flag

t5=ECap2Regs.CAP1;

t6=ECap2Regs.CAP2;

t7=ECap2Regs.CAP3;

t8= ECap2Regs.CAP4;

T3=t6-t5;T4=t8-t7;

}

//===========================================================================

// No more.

//===========================================================================

//Cap.Init.c

#include "DSP2833x_Device.h"

#include "DSP2833x_Examples.h"

void InitCapl(void)

{

ChoseCap();

InitECap1Gpio();

InitECap2Gpio();

SetCap1Mode();

SetCap2Mode();

}

void ChoseCap(void)

{

SysCtrlRegs.PCLKCR1.bit.ECAP1ENCLK=1;

SysCtrlRegs.PCLKCR1.bit.ECAP2ENCLK=1;

}

void InitECap1Gpio()

{

EALLOW;

GpioCtrlRegs.GPAPUD.bit.GPIO24=0;

GpioCtrlRegs.GPAQSEL2.bit.GPIO24=1;

GpioCtrlRegs.GPAMUX2.bit.GPIO24=1;

EDIS;

}

void InitECap2Gpio()

{

EALLOW;

GpioCtrlRegs.GPAPUD.bit.GPIO25=0;

GpioCtrlRegs.GPAQSEL2.bit.GPIO25=1;

GpioCtrlRegs.GPAMUX2.bit.GPIO25=1;

EDIS;

}

void SetCap1Mode(void)

{

ECap1Regs.ECCTL1.bit.CAP1POL=0;//捕获沿选择。上升沿捕获

ECap1Regs.ECCTL1.bit.CAP2POL=0;

ECap1Regs.ECCTL1.bit.CAP3POL=0;

ECap1Regs.ECCTL1.bit.CAP4POL=0;

ECap1Regs.ECCTL1.bit.CTRRST1=0;//CAP1事件中重置计数器。0-在CAP1事件中不重置计数器

ECap1Regs.ECCTL1.bit.CTRRST2=0;

ECap1Regs.ECCTL1.bit.CTRRST3=0;

ECap1Regs.ECCTL1.bit.CTRRST4=0;

ECap1Regs.ECCTL1.bit.CAPLDEN=1;

ECap1Regs.ECCTL1.bit.PRESCALE=0;//输入信号分频选择

ECap1Regs.ECCTL2.bit.CAP_APWM=0;//模式选择。0-捕捉模式，1-APWM模式

ECap1Regs.ECCTL2.bit.CONT_ONESHT=0;//1-单次模式，0-连续模式。

//疑惑：为什么配置为连续模式而不是单次模式

ECap1Regs.ECCTL2.bit.SYNCO_SEL=2;//同步输出选择。0-选择同步输入事件作为同步输出事件

//10或11：屏蔽同步信号输出

//疑惑:为什么屏蔽同步信号输出？？？

ECap1Regs.ECCTL2.bit.SYNCI_EN=0; //计数器（TSCTR）同步输入选择模式

ECap1Regs.ECEINT.all=0x0000; //失能中断

ECap1Regs.ECCLR.all=0xFFFF; //清除中断标志位

ECap1Regs.ECCTL2.bit.TSCTRSTOP=1;//启用计数器计数

ECap1Regs.ECEINT.bit.CEVT4=1; //???????????为什么只使能一路捕获事件4中断

}

void SetCap2Mode(void)

{

ECap2Regs.ECCTL1.bit.CAP1POL=1;//下降沿捕获

ECap2Regs.ECCTL1.bit.CAP2POL=1;

ECap2Regs.ECCTL1.bit.CAP3POL=1;

ECap2Regs.ECCTL1.bit.CAP4POL=1;

ECap2Regs.ECCTL1.bit.CTRRST1=0;//0-在CAP1事件中不重置计数器

ECap2Regs.ECCTL1.bit.CTRRST2=0;

ECap2Regs.ECCTL1.bit.CTRRST3=0;

ECap2Regs.ECCTL1.bit.CTRRST4=0;

ECap2Regs.ECCTL1.bit.CAPLDEN=1;//使能在捕获事件中加载CAP1-4寄存器时间

ECap2Regs.ECCTL1.bit.PRESCALE=0;//输入信号不分频

ECap2Regs.ECCTL2.bit.CAP_APWM=0;//0-选择CAP模式

ECap2Regs.ECCTL2.bit.CONT_ONESHT=0;//0-连续模式

ECap2Regs.ECCTL2.bit.SYNCO_SEL=2;//屏蔽同步信号输出

ECap2Regs.ECCTL2.bit.SYNCI_EN=0;//屏蔽同步输入操作

ECap2Regs.ECEINT.all=0x0000;//失能所有CAP中断

ECap2Regs.ECCLR.all=0xFFFF;//清除所有CAP中断标志

ECap2Regs.ECCTL2.bit.TSCTRSTOP=1;//1-计数器计数

ECap2Regs.ECEINT.bit.CEVT4=1;//1-捕获事件4中断使能

}

DSP28335的eCAP模块捕获脉冲问题

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