//###########################################################################
//
// FILE:    ECap_apwm_cpu01.c
//
// TITLE:   ECAP APWM Example
//
//! \addtogroup cpu01_example_list
//! <h1>ECAP APWM Example</h1>
//!
//! This program sets up the eCAP pins in the APWM mode.
//! This program runs at 200 MHz SYSCLK assuming a 20 MHz
//! OSCCLK.
//!
//! eCAP1 will come out on the GPIO5 pin
//! This pin is configured to vary between frequencies using
//! the shadow registers to load the next period/compare values
//!
//
//###########################################################################
// $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"

//
// Globals
//
Uint16 direction = 0;

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

//
// Initialize the GPIO pins for APWM1.
//
   InitAPwm1Gpio();

//
// 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.
// No __interrupts used for this example.
//

//
// Step 4. User specific code
//

//
// Setup APWM mode on CAP1, set period and compare registers
//
   ECap1Regs.ECCTL2.bit.CAP_APWM = 1;      // Enable APWM mode
   ECap1Regs.CAP1 = 0x01312D00;            // Set Period value
   ECap1Regs.CAP2 = 0x00989680;            // Set Compare value
   ECap1Regs.ECCLR.all = 0x0FF;            // Clear pending __interrupts
   ECap1Regs.ECEINT.bit.CTR_EQ_CMP = 1;    // enable Compare Equal Int

//
// Start counters
//
   ECap1Regs.ECCTL2.bit.TSCTRSTOP = 1;

   for(;;)
   {
        //
        // set next duty cycle to 50%
        //
        ECap1Regs.CAP4 = ECap1Regs.CAP1 >> 1;

        //
        // vary freq
        //
        if(ECap1Regs.CAP1 >= 0x01312D00)
        {
            direction = 0;
        }
        else if (ECap1Regs.CAP1 <= 0x00989680)
        {
            direction = 1;
        }

        if(direction == 0)
        {
            ECap1Regs.CAP3 = ECap1Regs.CAP1 - 500000;
        }
        else
        {
            ECap1Regs.CAP3 = ECap1Regs.CAP1 + 500000;
        }
   }
}

//
// End of file
//
