请教一下：关于GPIO的，

这是我的程序:

#include \"DSP28_Device.h\"
#include \"DSP28_Globalprototypes.h\"

// Prototype statements for functions found within this file.
// interrupt void ISRTimer2(void);
void delay_loop(void);
void Gpio_select(void);

unsigned int var1 = 0;
unsigned int var2 = 0;
unsigned int var3 = 0;
unsigned int var4 = 0;
unsigned int var5 = 0;

void main(void)
{

InitSysCtrl();

// Disable and clear all CPU interrupts:
DINT;
IER = 0x0000;
IFR = 0x0000;

// Initialize Pie Control Registers To Default State:
InitPieCtrl();

InitPieVectTable();


// Run GPIO test
var1= 0x00; // sets GPIO Muxs as I/Os
var2= 0x00; // sets GPIO DIR as inputs
var3= 0x00; // sets the Input qualifier values

Gpio_select();
// Toggle I/Os using DATA register for ever
GpioDataRegs.GPASET.all=0;
while(1)
{var2=GpioDataRegs.GPADAT.all;}
var3= 0x0000;
}

void Gpio_select(void)
{
EALLOW;

GpioMuxRegs.GPAMUX.all=var1;
GpioMuxRegs.GPBMUX.all=var1;
GpioMuxRegs.GPDMUX.all=var1;
GpioMuxRegs.GPFMUX.all=var1;
GpioMuxRegs.GPEMUX.all=var1;
GpioMuxRegs.GPGMUX.all=var1;

GpioMuxRegs.GPADIR.all=var2; // GPIO PORTs as input
GpioMuxRegs.GPBDIR.all=var2; // GPIO DIR select GPIOs as input
GpioMuxRegs.GPDDIR.all=var2;
GpioMuxRegs.GPEDIR.all=var2;
GpioMuxRegs.GPFDIR.all=var2;
GpioMuxRegs.GPGDIR.all=var2;

GpioMuxRegs.GPAQUAL.all=var3;
GpioMuxRegs.GPBQUAL.all=var3;
GpioMuxRegs.GPDQUAL.all=var3;
GpioMuxRegs.GPEQUAL.all=var3;

EDIS;

}

不知道为什么,GpioDataRegs.GPADAT.all读不出IO的电平,总是读为0xFFFC

你这程序根本看不出啥，都作了宏定义了
gpio就要先设置一下是作io口用；
然后设置方向，不复杂的

var2= 0x00; // sets GPIO DIR as inputs
你写了这个是方向变量，然后后面的死循环里

你又把读出的值给方向变量干啥，（猜是读值）

程序不全，就不瞎说了
竟然有个死循环，死循环后面竟然还有语句。这程序完全乱套。