CCS/LAUNCHXL-F28377S: Rotary encoder given wrong value

Tool/software: Code Composer Studio

Hello,

I am using a 1024 ppr rotary enconder with LAUNCHXL-F28377S via QEP_A pins. I am also using the serial communication port to send that to the computer to plot the speed x time graph. The problem is that when the motor is about 750 rpm the values comes with error. see the picture belllow.

//Part of the code from Example_posspeed.h

#define POSSPEED_DEFAULTS {0x0, 0x0,0x0,0x0,0x0,16382,2,0,0x0,\
                           50,0,6000,0,\
                           0,0,0,\
                           (void (*)(long))POSSPEED_Init,\
                           (void (*)(long))POSSPEED_Calc }

////////////////////////////////////////////////////////////////////////////////////////////////////////////

//Part from Example_posspeed.c

void  POSSPEED_Init(void)
{
    EQep1Regs.QUPRD = 2000000;            // Unit Timer for 100Hz at 200 MHz
                                          // SYSCLKOUT
    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 = 3;       //
    EQep1Regs.QCAPCTL.bit.CCPS = 6;       // 
    EQep1Regs.QCAPCTL.bit.CEN = 1;        // QEP Capture Enable
}

Does anyone have any idea how to solve this problem?