timer.c

TMS320F281X 定时器程序

//
//      Lab5 : TMS320F2812  Teaching CD ROM
//      (C) Frank Bormann
//
//###########################################################################
//
// FILE:	Lab5.c
//
// TITLE:	DSP28 T1PWM - output to generate a (square wave)note , 
//			CPU Timer0 ISR every 50 ms
//			Watchdog active , served in ISR and main-loop 
//
//###########################################################################
//
//  Ver | dd mmm yyyy | Who  | Description of changes
// =====|=============|======|===============================================
//  2.0 | 11 Nov 2003 | F.B. | adapted to header-files Version 1.00  
//###########################################################################

#include "DSP281x_Device.h"   

// Prototype statements for functions found within this file.

void Gpio_select(void);
void SpeedUpRevA(void);
void InitSystem(void);
interrupt void cpu_timer0_isr(void); // Prototype for Timer 0 Interrupt Service Routine

void main(void)
{
	unsigned int i;       
	unsigned long time_stamp;
	int frequency[8]={2219,1973,1776,1665,1480,1332,1184,1110};
		
	InitSystem();		// Initialize the DSP's core Registers
	
	// Speed_up the silicon A Revision. 
	// No need to call this function for Rev. C  later silicon versions

	
	Gpio_select();		// Setup the GPIO Multiplex Registers
	
	InitPieCtrl();		// Function Call to init PIE-unit ( code : DSP281x_PieCtrl.c)
	
	InitPieVectTable(); // Function call to init PIE vector table ( code : DSP281x_PieVect.c )
	
	// re-map PIE - entry for Timer 0 Interrupt 
	EALLOW;  // This is needed to write to EALLOW protected registers
   	PieVectTable.TINT0 = &cpu_timer0_isr;
   	EDIS;    // This is needed to disable write to EALLOW protected registers
	
	InitCpuTimers();
	
	// Configure CPU-Timer 0 to interrupt every 50 ms:
	// 150MHz CPU Freq, 50000 祍econds interrupt period
    ConfigCpuTimer(&CpuTimer0, 150, 50000);
    
    // Enable TINT0 in the PIE: Group 1 interrupt 7
   	PieCtrlRegs.PIEIER1.bit.INTx7 = 1;

	// Enable CPU INT1 which is connected to CPU-Timer 0:
    IER = 1;
    
	// Enable global Interrupts and higher priority real-time debug events:
   	EINT;   // Enable Global interrupt INTM
   	ERTM;   // Enable Global realtime interrupt DBGM
   	
   	// Configure EVA
    // Assumes EVA Clock is already enabled in InitSysCtrl();
    // Drive T1PWM / T2PWM by T1/T2 - logic
    EvaRegs.GPTCONA.bit.TCMPOE = 1;
   	// Polarity of GP Timer 1 Compare = Active low
	EvaRegs.GPTCONA.bit.T1PIN = 1;
	
    EvaRegs.T1CON.all = 0x1702;          	// Setup T1 count up mode
                                         	
   	CpuTimer0Regs.TCR.bit.TSS = 0;
   	
   	i = 0;
    
    time_stamp = 0;
    
	while(1)
	{    
  	    if ((CpuTimer0.InterruptCount%4)==0)
    	{
    	 	EALLOW;
    		SysCtrlRegs.WDKEY = 0xAA;		// and serve watchdog #2		
	    	EDIS;
    	}
    	if ((CpuTimer0.InterruptCount - time_stamp)>10)
    	{   
    		time_stamp = CpuTimer0.InterruptCount;
    		if(i<7) EvaRegs.T1PR = frequency[i++];
   	  		else  	EvaRegs.T1PR = frequency[14-i++]; 
	        EvaRegs.T1CMPR = EvaRegs.T1PR/2; 
	        EvaRegs.T1CON.bit.TENABLE = 1;
	        if (i>=14) i=0;
	   	}
	}
} 	

void Gpio_select(void)
{
	EALLOW;
	GpioMuxRegs.GPAMUX.all = 0x0;	// all GPIO port Pin's to I/O   
	GpioMuxRegs.GPAMUX.bit.T1PWM_GPIOA6 = 1; // T1PWM active
    GpioMuxRegs.GPBMUX.all = 0x0;   
    GpioMuxRegs.GPDMUX.all = 0x0;
    GpioMuxRegs.GPFMUX.all = 0x0;		 
    GpioMuxRegs.GPEMUX.all = 0x0; 
    GpioMuxRegs.GPGMUX.all = 0x0;			
										
    GpioMuxRegs.GPADIR.all = 0x0;	// GPIO PORT  as input
    GpioMuxRegs.GPBDIR.all = 0x00FF;	// GPIO Port B15-B8 input , B7-B0 output
    GpioMuxRegs.GPDDIR.all = 0x0;	// GPIO PORT  as input
    GpioMuxRegs.GPEDIR.all = 0x0;	// GPIO PORT  as input
    GpioMuxRegs.GPFDIR.all = 0x0;	// GPIO PORT  as input
    GpioMuxRegs.GPGDIR.all = 0x0;	// GPIO PORT  as input

    GpioMuxRegs.GPAQUAL.all = 0x0;	// Set GPIO input qualifier values to zero
    GpioMuxRegs.GPBQUAL.all = 0x0;
    GpioMuxRegs.GPDQUAL.all = 0x0;
    GpioMuxRegs.GPEQUAL.all = 0x0;
    EDIS;
}     



void InitSystem(void)
{
   	EALLOW;
   	SysCtrlRegs.WDCR= 0x00AF;		// Setup the watchdog 
   									// 0x00E8  to disable the Watchdog , Prescaler = 1
   									// 0x00AF  to NOT disable the Watchdog, Prescaler = 64
   	SysCtrlRegs.SCSR = 0; 			// Watchdog generates a RESET	
   	SysCtrlRegs.PLLCR.bit.DIV = 10;	// Setup the Clock PLL to multiply by 5
    
   	SysCtrlRegs.HISPCP.all = 0x1; // Setup Highspeed Clock Prescaler to divide by 2
   	SysCtrlRegs.LOSPCP.all = 0x2; // Setup Lowspeed CLock Prescaler to divide by 4
      	
   	// Peripheral clock enables set for the selected peripherals.   
   	SysCtrlRegs.PCLKCR.bit.EVAENCLK=1;
   	SysCtrlRegs.PCLKCR.bit.EVBENCLK=0;
   	SysCtrlRegs.PCLKCR.bit.SCIAENCLK=0;
   	SysCtrlRegs.PCLKCR.bit.SCIBENCLK=0;
   	SysCtrlRegs.PCLKCR.bit.MCBSPENCLK=0;
   	SysCtrlRegs.PCLKCR.bit.SPIENCLK=0;
   	SysCtrlRegs.PCLKCR.bit.ECANENCLK=0;
   	SysCtrlRegs.PCLKCR.bit.ADCENCLK=0;
   	EDIS;
}

interrupt void cpu_timer0_isr(void)
{
    CpuTimer0.InterruptCount++;
   	// Serve the watchdog every Timer 0 interrupt
   	EALLOW;
	SysCtrlRegs.WDKEY = 0x55;		// Serve watchdog #1
	EDIS;

   // Acknowledge this interrupt to receive more interrupts from group 1
   PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
//===========================================================================
// End of SourceCode.
//===========================================================================