example_2834xecap_apwm.c

德州儀器新款DSP TMS320C2834X 晶片 PWM 程式設計.

// TI File $Revision: /main/4 $
// Checkin $Date: May 5, 2008   17:02:42 $
//###########################################################################
//
// FILE:    Example_2834xECap_apwm.c
//
// TITLE:   DSP2834x ECAP APWM Example
//
// ASSUMPTIONS:
//
//    This program requires the DSP2834x 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 2834x 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    TI Test Only
//            1        1          1        0    SCI-A boot
//            1        1          0        1    SPI-A boot
//            1        1          0        0    I2C-A boot timing 1
//            1        0          1        1    eCAN-A boot timing 1
//            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    eCAN-A boot timing 2
//            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    I2C-A boot timing 2
//            0        0          0        1    Reserved
//            0        0          0        0    TI Test Only
//                                              Boot_Table_End$$
//
// DESCRIPTION:
//
//    This program sets up the eCAP pins in the APWM mode.
//    This program runs at 300/250/200 MHz SYSCLKOUT assuming a 20 MHz
//    XCLKIN
//
//    Watch eCAP1 on GPIO24 (use shadow registers to load the next period/compare values) - variable frequency
//    Watch eCAP2 on GPIO7 - APWM frequency output
//    Watch eCAP3 on GPIO9 - APWM frequency output
//    Watch eCAP4 on GPIO11 - APWM frequency output
//
//
//    Frequncy outputs on eCAP channels:
//    eCAP module     Device Frequency    APWM output frequency
//    ----------------------------------------------------------
//         1               300 MHz            15   Hz -  30 Hz
//                         250 MHz            12.5 Hz -  25 Hz
//                         200 MHz            10   Hz -  20 Hz
//         2               300 MHz            15   Hz
//                         250 MHz            12   Hz
//                         200 MHz            10   Hz
//         3               300 MHz			   3   Hz
//                         250 MHz             2.5 Hz
//                         200 MHz             2   Hz
//         4               300 MHz            60  kHz
//                         250 MHz            50  kHz
//                         200 MHz            40  kHz
//
//
//
//    Watch Variables:
//
//
//
//###########################################################################
// Original Author: D.F.
//
// $TI Release: C2834x Header Files V1.00 $
// $Release Date: February 25, 2009 $
//###########################################################################

#include "DSP28x_Project.h"     // Device Headerfile and 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 DSP2834x_SysCtrl.c file.
   InitSysCtrl();

// Step 2. Initalize GPIO:
// This example function is found in the DSP2834x_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 DSP2834x_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 DSP2834x_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 DSP2834x_DefaultIsr.c.
// This function is found in DSP2834x_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 DSP2834x_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 15 Hz and 30 Hz (for 300 MHz SYSCLKOUT)
      //                   12.5 Hz and 25 Hz (for 250 MHz SYSCLKOUT)
      //                   10 Hz and 20 Hz (for 200 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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