Hi sir/madam
My doubt is regarding the EQEP POSITION speed calulation for 28334 floating point dsp processor...i go through the EQEP POSITION SPEED C FILE GIVEN in the TI CONTROL SUITE and got an idea regarding the same....in that they have described for 150 mhz high speed calculation for a fixed point processor using iq math formats..can u please help me in making out the same for 2833x floating point dsp processor. i am involved in foc of IM which requires the same...
i ll give my sample code.can u please suggest what all modifications required for c coding..i am working with
1024 PPR QUADRATURE ENCODER,1440 RPM RATED SPEED MOTOR .
void Init_QEP(void)
{
//Encoder 1
EQep1Regs.QDECCTL.bit.QSRC=00; // QEP quadrature count mode
EQep1Regs.QEPCTL.bit.FREE_SOFT=2;
EQep1Regs.QEPCTL.bit.PCRM=00; // PCRM=00 mode - QPOSCNT reset on index event
EQep1Regs.QEPCTL.bit.UTE=1; // Unit Timeout Enable
EQep1Regs.QEPCTL.bit.QCLM=1; // Latch on unit time out
EQep1Regs.QPOSMAX=0xffffffff;
EQep1Regs.QEPCTL.bit.QPEN=1; // QEP enable
EQep1Regs.QCAPCTL.bit.UPPS=5; // 1/32 for unit position
EQep1Regs.QCAPCTL.bit.CCPS=7; // 1/128 for CAP clock
EQep1Regs.QCAPCTL.bit.CEN=1; // QEP Capture Enable
}
void speed(speed *p)
{
//Read from the on board rotary encoder (short J9, J10)
//Or external rotary encoder connected to J2 (open J9, J10)
// qepm=EQep1Regs.QPOSCNT&0xff;
// m = (0.866*qepm)/(255);
long tmp;
unsigned int pos16bval,temp1;
// _iq Tmp1,newp,oldp;
float Tmp1,newp,oldp=0,cal_angle=0;
//**** Position calculation - mechanical and electrical motor angle ****//
p->DirectionQep = EQep1Regs.QEPSTS.bit.QDF; // Motor direction: 0=CCW/reverse, 1=CW/forward
pos16bval=(unsigned int)EQep1Regs.QPOSCNT; // capture position once per QA/QB period
p->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 = Q26
tmp &= 0x03FFF000;
p->theta_mech = (int)(tmp>>11); // Q26 -> Q15
p->theta_mech &= 0x7FFF;
// The following lines calculate p->elec_mech
p->theta_elec = p->pole_pairs*p->theta_mech; // Q0*Q15 = Q15
p->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 Calcultation uyg 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 value
tmp = (long)((long)pos16bval*(long)p->mech_scaler); // Q0*Q26 = Q26
tmp &= 0x03FFF000;
tmp = (int)(tmp>>11); // Q26 -> Q15
tmp &= 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->spd = _IQ(-1);
else
p->spd = 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->spd = _IQmpy(p->BaseRpm,p->spd);
//=======================================
EQep1Regs.QCLR.bit.UTO=1; // Clear interrupt flag
}
//Read from the rotary encoder connected to J3
//AD7305_CH_B=EQep2Regs.QPOSCNT&0xff;
//display the result on AD7305 DAC channels A and B
//update_AD7305();
}
