PIC微控制器入門 PICC標頭檔案介紹

picc支援下的c程式**中一定要包含pic.h標頭檔案，該檔案安裝在ht-pic\include目錄下。它是很多標頭檔案的集合，c編譯器在pic.h中根據使用者選擇的晶元自動載入相應的其它標頭檔案，例如使用者選擇的晶元是pic16f877，則pic.h會把pic1687x.h載入；例如使用者選擇的晶元是pic16f877a，則pic.h會把pic168xa.h載入。載入的標頭檔案中其實是宣告晶元的暫存器和一些函式。例如以下程式片段：

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;

@符號表示位址的意思。這些宣告和pic彙編中的定義暫存器是差不多的。

例如：

tmr0 equ 0x01;
pcl equ 0x02;
status equ 0x03;
/*   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檔案的定義方法定義ram中檔案暫存器的方法，定義bank0的20h，21h，22h為檔案暫存器以及他們的位位址。

假設我們把

20h取名ram20h，其位位址分別是ram20h7~ram20h0

21h取名ram21h，其位位址分別是ram21h7~ram21h0

22h取名ram22h，其位位址分別是ram22h7~ram22h0

定義如下：

static volatile unsigned char ram20h @0x20;
static volatile unsigned char ram21h @0x21;
static volatile unsigned char ram22h @0x22;
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;
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標頭檔案中，或者直接寫在源程式中，這樣就可以直接對通過變數ram20h對bank0的20h單元進行位元組操作，可以通過ram20h7~ram20h0對bank0的20h單元進行位操作。例如：

#includemain()
}

以上程式假設ram20h、ram21h和ram22h的宣告已經加入到相應的標頭檔案中，那麼在源程式中就可以直接使用。

PIC微控制器入門 PICC標頭檔案介紹

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PIC微控制器入門 PICC標頭檔案介紹

PIC微控制器入門 PICC的指向RAM的指標

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