TI中文支持网想要测量编码器的A相和B相，如何用eqep测量编码器电机的位置和速度，应该设置哪些参数。
Susan Yang：
不知您现在使用的是哪款芯片？您可以在C2000WARE内查找相关的例程，如下
C:\ti\c2000\C2000Ware_2_00_00_02\device_support\f2837xd\examples\cpu1\eqep_pos_speed\cpu01
//###########################################################################
//
// FILE:Example_posspeed.c
//
// TITLE:Pos/speed measurement using EQEP peripheral
//
// DESCRIPTION:
//
// This file includes the EQEP initialization and position and speed
// calculation functions called by Eqep_posspeed.c.The position and speed
// calculation steps performed by POSSPEED_Calc() atSYSCLKOUT =200 MHz are
// described below:
//
// 1. This program calculates: **theta_mech**
//
//theta_mech = QPOSCNT/mech_Scaler = QPOSCNT/4000, where 4000 is the number
//of counts in 1 revolution.
//(4000/4 = 1000 line/rev. quadrature encoder)
//
// 2. This program calculates: **theta_elec**
//
//theta_elec = (# pole pairs) * theta_mech = 2*QPOSCNT/4000
//
// 3. This program calculates: **SpeedRpm_fr**
//
//SpeedRpm_fr = [(x2-x1)/4000]/T- Equation 1
//Note (x2-x1) = difference in number of QPOSCNT counts. Dividing (x2-x1)
//by 4000 gives position relative to Index in one revolution.
// If base RPM= 6000 rpm:6000 rpm = [(x2-x1)/4000]/10ms- Equation 2
//= [(x2-x1)/4000]/(.01s*1 min/60 sec)
//= [(x2-x1)/4000]/(1/6000) min
//max (x2-x1) = 4000 counts, or 1 revolution in 10 ms
//
//
// If both sides of Equation 2 are divided by 6000 rpm, then:
//1 = [(x2-x1)/4000] rev./[(1/6000) min * 6000rpm]
//Because (x2-x1) must be <4000 (max) for QPOSCNT increment,
//(x2-x1)/4000 < 1 for CW rotation
//And because (x2-x1) must be >-4000 for QPOSCNT decrement,
//(x2-x1)/4000>-1for CCW rotation
//speed_fr = [(x2-x1)/4000]/[(1/6000) min * 6000rpm]
//= (x2-x1)/4000- Equation 3
//
// To convert speed_fr to RPM, multiply Equation 3 by 6000 rpm
//SpeedRpm_fr = 6000rpm *(x2-x1)/4000- Final Equation
//
// 2. **min rpm ** = selected at 10 rpm based on CCPS prescaler options
//available (128 is greatest)
//
// 3. **SpeedRpm_pr**
//SpeedRpm_pr = X/(t2-t1)- Equation 4
//where X = QCAPCTL [UPPS]/4000 rev. (position relative to Index in
//1 revolution)
// Ifmax/base speed = 6000 rpm:
//6000 = (32/4000)/[(t2-t1)/(200MHz/64)]
//where 32 = QCAPCTL [UPPS] (Unit timeout - once every 32 edges)
//32/4000 = position in 1 revolution (position as a fraction
//of 1 revolution)
//t2-t1/(200MHz/64), t2-t1= # of QCAPCLK cycles, and
//QCAPCLK cycle = 1/(200MHz/64)
//= QCPRDLAT
//
// So:6000 rpm = [32(200MHz/64)*60s/min]/[4000(t2-t1)]
//t2-t1 = [32(200MHz/64)*60s/min]/(4000*6000rpm)- Equation 5
//= 250 CAPCLK cycles = maximum (t2-t1) = SpeedScaler
//
// Divide both sides by (t2-t1), and:
//1 = 32/(t2-t1) = [32(200MHz/64)*60 s/min]/(4000*6000rpm)]/(t2-t1)
//Because (t2-t1) must be < 250 for QPOSCNT increment:
//250/(t2-t1) < 1 for CW rotation
//And because (t2-t1) must be >-250 for QPOSCNT decrement:
//250/(t2-t1)> -1 for CCW rotation
//
//eed_pr = 250/(t2-t1)
//or [32(200MHz/64)*60 s/min]/(4000*6000rpm)]/(t2-t1) - Equation 6
//
// To convert speed_pr to RPM:
// Multiply Equation 6 by 6000rpm:
// SpeedRpm_fr= 6000rpm * [32(200MHz/64)*60 s/min]/[4000*6000rpm*(t2-t1)]
//= [32(200MHz/64)*60 s/min]/[4000*(t2-t1)]
//or [(32/4000)rev * 60 s/min]/[(t2-t1)(QCPRDLAT)]-Final Equation
//
// More detailed calculation results can be found in the Example_freqcal.xls
// spreadsheet included in the example folder.
//
// This file contains source for the posspeed module
//
//###########################################################################
// $TI Release: F2837xD Support Library v3.06.00.00 $
// $Release Date: Mon May 27 06:48:24 CDT 2019 $
// $Copyright:
// Copyright (C) 2013-2019 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without// modification, are permitted provided that the following conditions// are met:
////Redistributions of source code must retain the above copyright//notice, this list of conditions and the following disclaimer.
////Redistributions in binary form must reproduce the above copyright
//notice, this list of conditions and the following disclaimer in the//documentation and/or other materials provided with the//distribution.
////Neither the name of Texas Instruments Incorporated nor the names of
//its contributors may be used to endorse or promote products derived
//from this software without specific prior written permission.
//// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//###########################################################################//
// Included Files
//
#include "F28x_Project.h"
#include "Example_posspeed.h"//
// POSSPEED_Init - Initialize EQEP1 configuration
//
voidPOSSPEED_Init(void)
{EQep1Regs.QUPRD = 2000000;// Unit Timer for 100Hz at 200 MHz// SYSCLKOUTEQep1Regs.QDECCTL.bit.QSRC = 00;// QEP quadrature count modeEQep1Regs.QEPCTL.bit.FREE_SOFT = 2;EQep1Regs.QEPCTL.bit.PCRM = 00;// PCRM=00 mode - QPOSCNT reset on// index eventEQep1Regs.QEPCTL.bit.UTE = 1;// Unit Timeout EnableEQep1Regs.QEPCTL.bit.QCLM = 1;// Latch on unit time outEQep1Regs.QPOSMAX = 0xffffffff;EQep1Regs.QEPCTL.bit.QPEN = 1;// QEP enableEQep1Regs.QCAPCTL.bit.UPPS = 5;// 1/32 for unit positionEQep1Regs.QCAPCTL.bit.CCPS = 6;// 1/64 for CAP clockEQep1Regs.QCAPCTL.bit.CEN = 1;// QEP Capture Enable
}//
// POSSPEED_Calc - Perform the position calculations
//
void POSSPEED_Calc(POSSPEED *p)
{long tmp;unsigned int pos16bval,temp1;_iq Tmp1,newp,oldp;//// Position calculation - mechanical and electrical motor angle//p->DirectionQep = EQep1Regs.QEPSTS.bit.QDF;// Motor direction:// 0=CCW/reverse, 1=CW/forwardpos16bval = (unsigned int)EQep1Regs.QPOSCNT; // capture position once// per QA/QB periodp->theta_raw = pos16bval+ p->cal_angle;// raw theta = current pos. +// ang. offset from QA//// The following lines calculate// p->theta_mech ~= QPOSCNT/mech_scaler [current cnt/(total cnt in 1 rev.)]// where mech_scaler = 4000 cnts/revolution//tmp = (long)((long)p->theta_raw*(long)p->mech_scaler);// Q0*Q26 = Q26tmp &= 0x03FFF000;p->theta_mech = (int)(tmp>>11);// Q26 -> Q15p->theta_mech &= 0x7FFF;//// The following lines calculate p->elec_mech//p->theta_elec = p->pole_pairs*p->theta_mech;// Q0*Q15 = Q15p->theta_elec &= 0x7FFF;//// Check an index occurrence//if(EQep1Regs.QFLG.bit.IEL == 1){p->index_sync_flag = 0x00F0;EQep1Regs.QCLR.bit.IEL = 1;// Clear __interrupt flag}//// High Speed Calculation using QEP Position counter//// Check unit Time out-event for speed calculation:// Unit Timer is configured for 100Hz in INIT function//if(EQep1Regs.QFLG.bit.UTO == 1)// If unit timeout (one 100Hz period){//// Differentiator//// The following lines calculate// position = (x2-x1)/4000 (position in 1 revolution)//pos16bval = (unsigned int)EQep1Regs.QPOSLAT;// Latched POSCNT valuetmp = (long)((long)pos16bval*(long)p->mech_scaler); // Q0*Q26 = Q26tmp &= 0x03FFF000;tmp = (int)(tmp>>11);// Q26 -> Q15tmp &= 0x7FFF;newp = _IQ15toIQ(tmp);oldp = p->oldpos;if(p->DirectionQep==0)// POSCNT is counting down{if(newp>oldp){Tmp1 = - (_IQ(1) - newp + oldp);// x2-x1 should be negative}else{Tmp1 = newp -oldp;}}else if(p->DirectionQep == 1)// POSCNT is counting up{if(newp<oldp){Tmp1 = _IQ(1) + newp - oldp;}else{Tmp1 = newp - oldp;// x2-x1 should be positive}}if(Tmp1>_IQ(1)){p->Speed_fr = _IQ(1);}else if(Tmp1<_IQ(-1)){p->Speed_fr = _IQ(-1);}else{p->Speed_fr = Tmp1;}//// Update the electrical angle//p->oldpos = newp;//// Change motor speed from pu value to rpm value (Q15 -> Q0)// Q0 = Q0*GLOBAL_Q => _IQXmpy(), X = GLOBAL_Q//p->SpeedRpm_fr = _IQmpy(p->BaseRpm,p->Speed_fr);EQep1Regs.QCLR.bit.UTO=1;// Clear __interrupt flag}//// Low-speed computation using QEP capture counter//if(EQep1Regs.QEPSTS.bit.UPEVNT == 1)// Unit position event{if(EQep1Regs.QEPSTS.bit.COEF == 0)// No Capture overflow{temp1 = (unsigned long)EQep1Regs.QCPRDLAT; // temp1 = t2-t1}else// Capture overflow, saturate the result{temp1 = 0xFFFF;}//// p->Speed_pr = p->SpeedScaler/temp1//p->Speed_pr = _IQdiv(p->SpeedScaler,temp1);Tmp1 = p->Speed_pr;if (Tmp1>_IQ(1)){p->Speed_pr = _IQ(1);}else{p->Speed_pr = Tmp1;}//// Convert p->Speed_pr to RPM//if(p->DirectionQep == 0)// Reverse direction = negative{//// Q0 = Q0*GLOBAL_Q => _IQXmpy(), X = GLOBAL_Q//p->SpeedRpm_pr = -_IQmpy(p->BaseRpm,p->Speed_pr);}else// Forward direction = positive{//// Q0 = Q0*GLOBAL_Q => _IQXmpy(), X = GLOBAL_Q//p->SpeedRpm_pr = _IQmpy(p->BaseRpm,p->Speed_pr);}EQep1Regs.QEPSTS.all = 0x88; // Clear Unit position event flag// Clear overflow error flag}
}//
// End of file
//
