css_cmake_test/f2833x/examples/eqep_freqcal/Example_2833xEqep_freqcal.c

//###########################################################################
//
// FILE:   Example_2833xEqep_freqcal.c
//
// TITLE:  eQEP, Frequency measurement Example
//
//! \addtogroup f2833x_example_list
//! <h1>eQEP, Frequency measurement (eqep_freqcal)</h1>
//!
//!  This test will calculate the frequency and period of an input signal
//!  using eQEP module.
//!
//!  EPWM1A is configured to generate a frequency of 5 kHz.
//!  \sa section on Frequency Calculation for more details on the frequency 
//!  calculation performed in this example.
//!
//!  In addition to the main example file, the following files must be included
//!  in this project:
//!  - \b Example_freqcal.c , includes all eQEP functions
//!  - \b Example_EPwmSetup.c , sets up EPWM1A for use with this example
//!  - \b Example_freqcal.h , includes initialization values for frequency 
//!       structure.
//!
//!  The configuration for this example is as follows
//!  - Maximum frequency is configured to 10KHz (BaseFreq)
//!  - Minimum frequency is assumed at 50Hz for capture pre-scalar selection
//!
//!  \b SPEED_FR: High Frequency Measurement is obtained by counting the 
//!  external input pulses for 10ms (unit timer set to 100Hz).
//!  \f[ SPEED\_FR = \frac{Count\ Delta}{10ms} \f]
//!
//!  \b SPEED_PR: Low Frequency Measurement is obtained by measuring time 
//!  period of input edges.
//!  Time measurement is averaged over 64edges for better results and
//!  capture unit performs the time measurement using pre-scaled SYSCLK
//!
//!  Note that pre-scaler for capture unit clock is selected such that
//!  capture timer does not overflow at the required minimum frequency
//!  This example runs forever until the user stops it.
//!
//!  \b External \b Connections \n
//!  - Connect GPIO20/EQEP1A to GPIO0/EPWM1A
//!
//!  \b Watch \b Variables \n
//!  - \b freq.freqhz_fr , Frequency measurement using position counter/unit 
//!       time out
//!  - \b freq.freqhz_pr , Frequency measurement using capture unit
//
//###########################################################################
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//###########################################################################

//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File
#include "Example_freqcal.h"    // Example specific include file

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

//
// Globals
//
FREQCAL freq=FREQCAL_DEFAULTS;

//
// Main
//
void main(void)
{
    //
    // Step 1. Initialize System Control:
    // PLL, WatchDog, enable Peripheral Clocks
    // This example function is found in the DSP2833x_SysCtrl.c file.
    //
    InitSysCtrl();

    //
    // Step 2. Initialize GPIO:
    // This example function is found in the DSP2833x_Gpio.c file and
    // illustrates how to set the GPIO to it's default state.
    //
    // InitGpio();  // Skipped for this example

    //
    // Only init the GPIO for EQep1 and EPwm1 in this case
    // This function is found in DSP2833x_EQep.c
    //
    InitEQep1Gpio();
    InitEPwm1Gpio();

    //
    // 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 DSP2833x_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 DSP2833x_DefaultIsr.c.
    // This function is found in DSP2833x_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:
    //
    
    //
    // Example specific ePWM setup.  This function is found in 
    // Example_EPwmSetup.c
    //
    EPwmSetup();

    //
    // 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

    //
    // Initializes eQEP for frequency calculation in FREQCAL_Init(void)function
    // in Example_EPwmSetup.c
    //
    freq.init(&freq);         

    for(;;)
    {
        
    }
}

//
// prdTick - Interrupts once per ePWM period
//
__interrupt void 
prdTick(void)
{
    //
    // Checks for event and calculates frequency in FREQCAL_Calc(FREQCAL *p)
    // function in Example_EPwmSetup.c
    //
    freq.calc(&freq); 
    
    //
    // Acknowledge this interrupt to receive more interrupts from group 1
    //
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP3;
    EPwm1Regs.ETCLR.bit.INT=1;
}

//
// End of File
//