example_2833xecap_apwm.c

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// TI File $Revision: /main/9 $
// Checkin $Date: August 10, 2007   09:04:32 $
//###########################################################################
//
// FILE:    Example_2833xECap_apwm.c
//
// TITLE:   DSP2833x ECAP APWM Example
//
// ASSUMPTIONS:
//
//    This program requires the DSP2833x header files.
//
//    Monitor eCAP1 - eCAP4 pins on a oscilloscope as
//    described below.
//
//       eCAP1 on GPIO24
//       eCAP2 on GPIO7
//       eCAP3 on GPIO9
//       eCAP4 on GPIO11
//
//    As supplied, this project is configured for "boot to SARAM"
//    operation.  The 2833x Boot Mode table is shown below.
//    For information on configuring the boot mode of an eZdsp,
//    please refer to the documentation included with the eZdsp,
//
//       $Boot_Table:
//
//         GPIO87   GPIO86     GPIO85   GPIO84
//          XA15     XA14       XA13     XA12
//           PU       PU         PU       PU
//        ==========================================
//            1        1          1        1    Jump to Flash
//            1        1          1        0    SCI-A boot
//            1        1          0        1    SPI-A boot
//            1        1          0        0    I2C-A boot
//            1        0          1        1    eCAN-A boot
//            1        0          1        0    McBSP-A boot
//            1        0          0        1    Jump to XINTF x16
//            1        0          0        0    Jump to XINTF x32
//            0        1          1        1    Jump to OTP
//            0        1          1        0    Parallel GPIO I/O boot
//            0        1          0        1    Parallel XINTF boot
//            0        1          0        0    Jump to SARAM	    <- "boot to SARAM"
//            0        0          1        1    Branch to check boot mode
//            0        0          1        0    Boot to flash, bypass ADC cal
//            0        0          0        1    Boot to SARAM, bypass ADC cal
//            0        0          0        0    Boot to SCI-A, bypass ADC cal
//                                              Boot_Table_End$
//
// DESCRIPTION:
//
//    This program sets up the eCAP pins in the APWM mode.
//    This program runs at 150 MHz SYSCLKOUT assuming a 30 MHz
//    XCLKIN or 100 MHz SYSCLKOUT assuming a 20 MHz XCLKIN.
//
//    For 150 MHz devices:
//
//    eCAP1 will come out on the GPIO24 pin
//    This pin is configured to vary between 7.5 Hz and 15 Hz using
//    the shadow registers to load the next period/compare values
//
//    eCAP2 will come out on the GPIO7 pin
//    this pin is configured as a 7.5 Hz output
//
//    eCAP3 will come out on the GPIO9 pin
//    this pin is configured as a 1.5 Hz output
//
//
//    eCAP4 will come out on the GPIO11 pin
//    this pin is configured as a 30 kHz output
//
//    All frequencies assume a 30 Mhz input clock. The XCLKOUT pin
//    should show 150Mhz.
//    --------------------------------------------------------------
//    For 100 MHz devices:
//
//    eCAP1 will come out on the GPIO24 pin
//    This pin is configured to vary between 5 Hz and 10 Hz using
//    the shadow registers to load the next period/compare values
//
//    eCAP2 will come out on the GPIO7 pin
//    this pin is configured as a 5 Hz output
//
//    eCAP3 will come out on the GPIO9 pin
//    this pin is configured as a 1 Hz output
//
//    eCAP4 will come out on the GPIO11 pin
//    this pin is configured as a 20kHz output
//
//    All frequencies assume a 20 Mhz input clock. The XCLKOUT pin
//    should show 100Mhz.
//
//
//    Watch Variables:
//
//
//
//###########################################################################
// Original Author: D.F.
//
// $TI Release: DSP2833x Header Files V1.01 $
// $Release Date: September 26, 2007 $
//###########################################################################

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File
#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

// Global variables
Uint16 direction = 0;

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. Initalize 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

// Initialize the GPIO pins for eCAP.
// This function is found in the DSP2833x_ECap.c file
   InitECapGpio();

// 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.
// No interrupts used for this example.

// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP2833x_InitPeripherals.c
// InitPeripherals(); // Not required for this example

// Step 5. 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

   // Setup APWM mode on CAP2, set period and compare registers
   ECap2Regs.ECCTL2.bit.CAP_APWM = 1;	// Enable APWM mode
   ECap2Regs.CAP1 = 0x01312D00;			// Set Period value
   ECap2Regs.CAP2 = 0x00989680;			// Set Compare value
   ECap2Regs.ECCLR.all = 0x0FF;			// Clear pending interrupts
   ECap1Regs.ECEINT.bit.CTR_EQ_CMP = 1; // enable Compare Equal Int

   // Setup APWM mode on CAP3, set period and compare registers
   ECap3Regs.ECCTL2.bit.CAP_APWM = 1;	// Enable APWM mode
   ECap3Regs.CAP1 = 0x05F5E100;			// Set Period value
   ECap3Regs.CAP2 = 0x02FAF080;			// Set Compare value
   ECap3Regs.ECCLR.all = 0x0FF;			// Clear pending interrupts
   ECap1Regs.ECEINT.bit.CTR_EQ_CMP = 1; // enable Compare Equal Int

   // Setup APWM mode on CAP4, set period and compare registers
   ECap4Regs.ECCTL2.bit.CAP_APWM = 1;	// Enable APWM mode
   ECap4Regs.CAP1 = 0x00001388;			// Set Period value
   ECap4Regs.CAP2 = 0x000009C4;			// Set Compare value
   ECap4Regs.ECCLR.all = 0x0FF;			// Clear pending interrupts
   ECap1Regs.ECEINT.bit.CTR_EQ_CMP = 1; // enable Compare Equal Int

   // Start counters
   ECap1Regs.ECCTL2.bit.TSCTRSTOP = 1;
   ECap2Regs.ECCTL2.bit.TSCTRSTOP = 1;
   ECap3Regs.ECCTL2.bit.TSCTRSTOP = 1;
   ECap4Regs.ECCTL2.bit.TSCTRSTOP = 1;

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

      // vary freq between 7.5 Hz and 15 Hz (for 150MHz SYSCLKOUT) 5 Hz and 10 Hz (for 100 MHz SYSCLKOUT)
      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;
      }
   }

}



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