PICC支持下的C程序代碼中一定要包含pic.h頭文件,，該文件安裝在HT-PIC\include目錄下,。它是很多頭文件的集合,，C編譯器在pic.h中根據(jù)用戶選擇的芯片自動載入相應的其它頭文件，例如用戶選擇的芯片是PIC16F877,，則pic.h會把pic1687x.h載入,；例如用戶選擇的芯片是PIC16F877A，則pic.h會把pic168xa.h載入,。載入的頭文件中其實是聲明芯片的寄存器和一些函數(shù),。例如以下程序片段：

static volatile unsigned char PORTA@ 0x05;

static volatile unsigned char PORTB@ 0x06;

static        unsigned char bank1 OPTION@ 0x81;

static        unsigned char bank1 TRISA@0x85;

static        unsigned char bank1 TRISB @0x86;

@符號表示地址的意思。這些聲明和PIC匯編中的定義寄存器是差不多的,。

例如：

TMR0 EQU 0x01;

PCL EQU 0x02;

STATUS EQU 0X03;

對于特殊功能寄存器的位地址在頭文件中也有定義,，比如PORTB端口的位地址定義如下：

/*   PORTB bits   */

static volatile bit  RB7  @ (unsigned)&PORTB*8+7;

static volatile bit  RB6  @ (unsigned)&PORTB*8+6;

static volatile bit  RB5  @ (unsigned)&PORTB*8+5;

static volatile bit  RB4  @ (unsigned)&PORTB*8+4;

static volatile bit  RB3  @ (unsigned)&PORTB*8+3;

static volatile bit  RB2  @ (unsigned)&PORTB*8+2;

static volatile bit  RB1  @ (unsigned)&PORTB*8+l;

static volatile bit  RB0  @ (unsigned)&PORTB*8+0;

其中RB7代表PORTB的bit7。

我們可以模仿pic.h文件的定義方法定義RAM中文件寄存器的方法,，定義bank0的20h,，21h，22h為文件寄存器以及他們的位地址,。

假設我們把

20h取名RAM20H,，其位地址分別是RAM20H7~RAM20H0

21h取名RAM21H，其位地址分別是RAM21H7~RAM21H0

22h取名RAM22H,，其位地址分別是RAM22H7~RAM22H0

定義如下：

static volatile unsigned char RAM20H @0x20;

static volatile unsigned char RAM21H @0x21;

static volatile unsigned char RAM22H @0x22;

RAM20H的位地址定義如下：

static volatile bit RAM20H7 @(unsigned)&RAM20H*8+7;

static volatile bit RAM20H6 @(unsigned)&RAM20H*8+6;

static volatile bit RAM20H5 @(unsigned)&RAM20H*8+5;

static volatile bit RAM20H4 @(unsigned)&RAM20H*8+4;

static volatile bit RAM20H3 @(unsigned)&RAM20H*8+3;

static volatile bit RAM20H2 @(unsigned)&RAM20H*8+2;

static volatile bit RAM20H1 @(unsigned)&RAM20H*8+1;

static volatile bit RAM20H0 @(unsigned)&RAM20H*8+0; 

RAH21H和RAH22H的位地址也可以類似定義：

static volatile bit RAM21H7 @(unsigned)&RAM21H*8+7;

static volatile bit RAM21H6 @(unsigned)&RAM21H*8+6;

static volatile bit RAM21H5 @(unsigned)&RAM21H*8+5;

static volatile bit RAM21H4 @(unsigned)&RAM21H*8+4;

static volatile bit RAM21H3 @(unsigned)&RAM21H*8+3;

static volatile bit RAM21H2 @(unsigned)&RAM21H*8+2;

static volatile bit RAM21H1 @(unsigned)&RAM21H*8+1;

static volatile bit RAM21H0 @(unsigned)&RAM21H*8+0;

static volatile bit RAM22H7 @(unsigned)&RAM22H*8+7;

static volatile bit RAM22H6 @(unsigned)&RAM22H*8+6;

static volatile bit RAM22H5 @(unsigned)&RAM22H*8+5;

static volatile bit RAM22H4 @(unsigned)&RAM22H*8+4;

static volatile bit RAM22H3 @(unsigned)&RAM22H*8+3;

static volatile bit RAM22H2 @(unsigned)&RAM22H*8+2;

static volatile bit RAM22H1 @(unsigned)&RAM22H*8+1;

static volatile bit RAM22H0 @(unsigned)&RAM22H*8+0;

將這些定義加入到相應的頭文件中,，或者直接寫在源程序中，這樣就可以直接對通過變量RAM20H對bank0的20h單元進行字節(jié)操作,，可以通過RAM20H7~RAM20H0對bank0的20h單元進行位操作,。例如：

#include

main()

{  

RAM20H=0x20;   //把0x20賦值給20h

RAM21H=0x21;   //把0x21賦值給21h

RAM22H= RAM20H+ RAM21H;

while(1) {  ;   }

}

以上程序假設RAM20H、RAM21H和RAM22H的聲明已經(jīng)加入到相應的頭文件中,，那么在源程序中就可以直接使用,。