//###########################################################################
//
// FILE:    Eqep_pos_speed.c
//
// TITLE:    EQEP Speed and Position measurement
//
//! \addtogroup cpu01_example_list
//! <h1>EQEP Speed and Position Measurement (Eqep_pos_speed)</h1>
//!
//! This example provides position measurement,speed measurement using the
//! capture unit, and speed measurement using unit time out. This example
//! uses the IQMath library. It is used merely to simplify high-precision
//! calculations.
//! The example requires the following hardware connections from EPWM1 and
//! GPIO pins (simulating QEP sensor) to QEP peripheral.
//!    - GPIO20/eQEP1A <- GPIO0/ePWM1A (simulates eQEP Phase A signal)
//!    - GPIO21/eQEP1B <- GPIO1/ePWM1B (simulates eQEP Phase B signal)
//!    - GPIO23/eQEP1I <- GPIO4 (simulates eQEP Index Signal)
//!
//! See DESCRIPTION in Example_posspeed.c for more details on the calculations
//! performed in this example.
//! In addition to this file, the following files must be included in this
//! project:
//!    - Example_posspeed.c - includes all eQEP functions
//!    - Example_EPwmSetup.c - sets up ePWM1A and ePWM1B as simulated QA and QB
//!                            encoder signals
//!    - Example_posspeed.h - includes initialization values for pos and speed
//!                           structure
//!
//! Note:
//!    - Maximum speed is configured to 6000rpm(BaseRpm)
//!    - Minimum speed is assumed at 10rpm for capture pre-scalar selection
//!    - Pole pair is configured to 2 (pole_pairs)
//!    - QEP Encoder resolution is configured to 4000counts/revolution
//!      (mech_scaler)
//!    - Which means: 4000/4 = 1000 line/revolution quadrature encoder
//!      (simulated by EPWM1)
//!    - EPWM1 (simulating QEP encoder signals) is configured for 5kHz
//!      frequency or 300 rpm (=4*5000 cnts/sec * 60 sec/min)/4000 cnts/rev)
//!    - SPEEDRPM_FR: High Speed Measurement is obtained by counting the QEP
//!                   input pulses for 10ms (unit timer set to 100Hz).
//!    - SPEEDRPM_FR = (Position Delta/10ms) * 60 rpm
//!    - SPEEDRPM_PR: Low Speed Measurement is obtained by measuring time
//!                   period of QEP edges. Time measurement is averaged over
//!                   64edges for better results and capture unit performs the
//!                   time measurement using pre-scaled SYSCLK
//!    - Pre-scaler for capture unit clock is selected such that capture timer
//!      does not overflow at the required minimum RPM speed.
//!
//! \b External \b Connections \n
//!   - Connect eQEP1A(GPIO20) to ePWM1A(GPIO0)(simulates eQEP Phase A signal)
//!   - Connect eQEP1B(GPIO21) to ePWM1B(GPIO1)(simulates eQEP Phase B signal)
//!   - Connect eQEP1I(GPIO23) to GPIO4 (simulates eQEP Index Signal)
//!
//! \b Watch \b Variables \n
//!  - qep_posspeed.SpeedRpm_fr - Speed meas. in rpm using QEP position counter
//!  - qep_posspeed.SpeedRpm_pr - Speed meas. in rpm using capture unit
//!  - qep_posspeed.theta_mech  - Motor mechanical angle (Q15)
//!  - qep_posspeed.theta_elec  - Motor electrical angle (Q15)
//!
//
//###########################################################################
// $TI Release: F2837xD Support Library v210 $
// $Release Date: Tue Nov  1 14:46:15 CDT 2016 $
// $Copyright: Copyright (C) 2013-2016 Texas Instruments Incorporated -
//             http://www.ti.com/ ALL RIGHTS RESERVED $
//###########################################################################

//
// Included Files
//
#include "F28x_Project.h"
#include "Example_posspeed.h"

//
// Globals
//
POSSPEED qep_posspeed=POSSPEED_DEFAULTS;
Uint16 Interrupt_Count = 0;

//
// Function Prototypes
//
void initEpwm();
__interrupt void prdTick(void);

//
// Main
//
void main(void)
{
//
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the F2837xD_SysCtrl.c file.
//
   InitSysCtrl();

//
// Step 2. Initialize GPIO:
// This example function is found in the F2837xD_Gpio.c file and
// illustrates how to set the GPIO to its default state.
//
// InitGpio();  // Skipped for this example

//
// For this case only init GPIO for eQEP1 and ePWM1
// This function is found in F2837xD_EQep.c
//
   InitEQep1Gpio();
   InitEPwm1Gpio();
   EALLOW;
   GpioCtrlRegs.GPADIR.bit.GPIO4 = 1; // GPIO4 as output simulates Index signal
   GpioDataRegs.GPACLEAR.bit.GPIO4 = 1;  // Normally low
   EDIS;

//
// Step 3. Clear all __interrupts and initialize PIE vector table:
// Disable CPU __interrupts
//
   DINT;

//
// Initialize the PIE control registers to their default state.
// The default state is all PIE __interrupts disabled and flags
// are cleared.
// This function is found in the F2837xD_PieCtrl.c file.
//
   InitPieCtrl();

//
// Disable CPU __interrupts and clear all CPU __interrupt flags:
//
   IER = 0x0000;
   IFR = 0x0000;

//
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the __interrupt
// is not used in this example.  This is useful for debug purposes.
// The shell ISR routines are found in F2837xD_DefaultIsr.c.
// This function is found in F2837xD_PieVect.c.
//
   InitPieVectTable();

//
// Interrupts that are used in this example are re-mapped to
// ISR functions found within this file.
//
   EALLOW;  // This is needed to write to EALLOW protected registers
   PieVectTable.EPWM1_INT= &prdTick;
   EDIS;    // This is needed to disable write to EALLOW protected registers

//
// Step 4. Initialize all the Device Peripherals:
//
   initEpwm();  // This function exists in Example_EPwmSetup.c

//
// Step 5. User specific code, enable __interrupts:
// Enable CPU INT1 which is connected to CPU-Timer 0:
//
   IER |= M_INT3;

//
// Enable TINT0 in the PIE: Group 3 __interrupt 1
//
   PieCtrlRegs.PIEIER3.bit.INTx1 = 1;

//
// Enable global Interrupts and higher priority real-time debug events:
//
   EINT;   // Enable Global __interrupt INTM
   ERTM;   // Enable Global realtime __interrupt DBGM

   qep_posspeed.init(&qep_posspeed);

   for(;;)
   {
   }
}

//
// prdTick - EPWM1 Interrupts once every 4 QCLK counts (one period)
//
__interrupt void prdTick(void)
{
    Uint16 i;

   //
   // Position and Speed measurement
   //
   qep_posspeed.calc(&qep_posspeed);

   //
   // Control loop code for position control & Speed control
   //
   Interrupt_Count++;

   //
   // Every 1000 __interrupts(4000 QCLK counts or 1 rev.)
   //
   if (Interrupt_Count==1000)
   {
       EALLOW;
       GpioDataRegs.GPASET.bit.GPIO4 = 1; // Pulse Index signal  (1 pulse/rev.)
       for (i=0; i<700; i++)
       {
       }
       GpioDataRegs.GPACLEAR.bit.GPIO4 = 1;
       Interrupt_Count = 0;               // Reset count
       EDIS;
   }

   //
   // Acknowledge this __interrupt to receive more __interrupts from group 1
   //
   PieCtrlRegs.PIEACK.all = PIEACK_GROUP3;
   EPwm1Regs.ETCLR.bit.INT=1;
}

//
// End of file
//
