example_281xstandbywake.c

281x例程

// TI File $Revision: /main/1 $
// Checkin $Date: April 9, 2007   17:05:21 $
//###########################################################################
//
// FILE:    Example_281xStandbyWake.c
//
// TITLE:   Device Standby Mode and Wakeup Program.
//
// ASSUMPTIONS:
//
//    This program requires the DSP281x header files.
//
//    To observe when device wakes from STANDBY mode, monitor
//    GPIO1 with an oscilloscope (set to 1 in WAKEINT ISR)
//
//    As supplied, this project is configured for "boot to SARAM"
//    operation.  The 281x 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      GPIO18     GPIO29    GPIO34
//       Mode      SPICLKA    SCITXDA
//                 SCITXB
//       -------------------------------------
//       Flash       1          1        1
//       SCI-A       1          1        0
//       SPI-A       1          0        1
//       I2C-A       1          0        0
//       ECAN-A      0          1        1
//       SARAM       0          1        0  <- "boot to SARAM"
//       OTP         0          0        1
//       I/0         0          0        0
//
//
// DESCRIPTION:
//
//    This example puts the device into STANDBY mode. If the lowest
//    possible current consumption in STANDBY mode is desired, the
//    JTAG connector must be removed from the device board while
//    the device is in STANDBY mode.
//
//    The example then wakes up the device from STANDBY using the
//    watchdog interrupt. When the Watchdog counter overflows,
//    a WAKEINT interrupt is triggered, waking the device from
//    Standby mode. GPIO1 can then be observed to go high.
//
//###########################################################################
// $TI Release: DSP281x Header Files V1.11 $
// $Release Date: September 26, 2007 $
//###########################################################################

#include "DSP281x_Device.h"
#include "DSP281x_Examples.h"

// Prototype statements for functions found within this file.

interrupt void WAKE_ISR(void);  	// ISR for WAKEINT

void main()

{

// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP281x_SysCtrl.c file.
   InitSysCtrl();
   

// Step 2. Initalize GPIO:
// This example function is found in the DSP281x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio();  // Skipped for this example

    EALLOW;
	GpioMuxRegs.GPADIR.all = 0xFFFF;	        // All pins are outputs 
    GpioDataRegs.GPACLEAR.bit.GPIOA1=1;
	GpioDataRegs.GPADAT.all = 0x0000;	        // All I/O pins are driven low
  	EDIS;

// 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 DSP281x_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 DSP281x_DefaultIsr.c.
// This function is found in DSP281x_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.WAKEINT = &WAKE_ISR;
   EDIS;

// Step 4. Initialize all the Device Peripherals:
// Not applicable for this example.

// Step 5. User specific code, enable interrupts:

// Enable CPU INT1 which is connected to WakeInt:
   IER |= M_INT1;

// Enable WAKEINT in the PIE: Group 1 interrupt 8
   PieCtrlRegs.PIEIER1.bit.INTx8 = 1;
   PieCtrlRegs.PIEACK.bit.ACK1 = 1;
// Enable global Interrupts:
   EINT;   // Enable Global interrupt INTM

// Choose qualification cycles in LPMCR0 register 
	SysCtrlRegs.LPMCR0.bit.QUALSTDBY = 0;	// The wakeup signal should be (2+QUALSTDBY) OSCCLKs wide.

// Write the LPM code value
    EALLOW;
    SysCtrlRegs.LPMCR0.bit.LPM = 0x0001;   // LPM mode = Standby 
	SysCtrlRegs.LPMCR1.bit.WDINT = 0x0001; // WAKEINT wakes device from idle
    SysCtrlRegs.SCSR = 0x0002;             // Enable Watchdog Interrupts
    SysCtrlRegs.WDCR= 0x0028;              // Enable Watchdog 
    KickDog();                             // Service Watchdog to reset counter   
    EDIS;
// Force device into STANDBY
    while ((SysCtrlRegs.SCSR&0x0004)!=0x0004){}; // Wait until watchdog interrupt signal is not active
	asm(" IDLE");                           // Device waits in IDLE until falling edge on GPIO0/XNMI pin
	                                        // wakes device from Standby mode.
	while(1){}								// Loop here after wake-up.

}

/* ----------------------------------------------- */
/* ISR for WAKEINT - Will be executed when         */
/* Watchdog Interrupt triggers                     */
/* ------------------------------------------------*/
interrupt void WAKE_ISR(void)
{
   GpioDataRegs.GPASET.bit.GPIOA1 = 1;	// Set GPIO1 in the ISR - monitored with oscilloscope
   PieCtrlRegs.PIEACK.bit.ACK1 = 1;
   DisableDog();                        // Disable the watchdog.  This ISR will not be entered again.
   return;
}