给开发板接了个LED和开关，简单写了个测试程序：

/*
* File:   key_led.c
* Author: Administrator
*
* Created on 2015?3?23?, ??6:40
*/

#include "xc.h"
_FOSCSEL
(
    FNOSC_FRC &  // Oscillator Select (8MHz FRC with Postscaler (FRCDIV))
  //  SOSCSRC_ANA &   // SOSC Source Type (Analog Mode for use with crystal)
  //  LPRCSEL_HP &    // LPRC Power and Accuracy (High Power/High Accuracy)
    IESO_ON         // Internal External Switch Over bit (Internal External Switchover mode enabled (Two-speed Start-up enabled))
)
_FOSC
(
   // POSCMD_HS &   // Primary Oscillator Mode (Primary oscillator disabled)
    OSCIOFNC_ON &   // CLKO Enable Configuration bit (CLKO output signal enabled)
    POSCFREQ_MS &   // Primary Oscillator Frequency Range Configuration bits (Primary oscillator/external clock frequency between 100kHz to 8MHz)
    SOSCSEL_SOSCHP &// SOSC Power Selection Configuration bits (Secondary Oscillator configured for high-power operation)
    FCKSM_CSECME    // Clock Switching and Monitor Selection (Clock Switching and Fail-safe Clock Monitor Enabled)
)
void delay(unsigned int uiCnt)
{
    int i,j;
    for(i=0;i<uiCnt;i++)
        for(j=0;j<110;j++);
}
int main(void) {
    //ANSA = 0b0000000000000000;
    //ANSB = 0b0000000000000000;
    ANSAbits.ANSA1 = 0;  //选通为数字输入
    TRISBbits.TRISB3 = 0; //IO的方向为输出
    TRISAbits.TRISA0 = 0; 
    TRISAbits.TRISA1 = 1; //IO的方向设为输入
    TRISBbits.TRISB14 = 1;
    
    while(1)
    {
        if(PORTAbits.RA1) //如果按下，则拉高电平.
        {
           // LATAbits.LATA0 = 1;
            LATBbits.LATB3 = 1;
            delay(1000);
        }
        else
            //LATAbits.LATA0 = 0;
            LATBbits.LATB3 = 0;
        delay(500);
       LATAbits.LATA0 ^= 1; //心跳DEBUG灯，开发板自带的.
        
    }
    
    return 0;
}
当接在PORTA1上的按钮，按下时，接到PORTB3上的LED会发光。全程使用到了基本的输入输出的基本的寄存器的操作。