嵌入式C语言和汇编语言的混合编程

此文章简单介绍 单片机 C语言和汇编语言混合编程的例子。主要用单片机汇编语言编写DS1302的底层驱动，在C语言里通过调用汇编语言，从而实现C和汇编的混合编程。

;汇编语言源文件

;======================================

; DS1302 DRIVER.

;EMBEDY ASSEMBLY LANGUAGE.

;WHEN CHAR-STYLE (R7,R5,R3) RETURN(R7)

;INT ..."_"--_FUNCTION TELL HAVE PARA TRANS.

;PROGRAMER : MicroAC

;DATE : 2012.03.10

;======================================

NAME DS1302 ;MODULE NAME

;DS1302时钟IC控制

CS BIT P1.2

SDA BIT P1.1

SCL BIT P1.0

FLAG BIT 20H.1

;**************************************

;--Initial : DS1302 with Assembly L

;--Programer : MicroAC

;--Date : 2012.03.10

;**************************************

;?CODE ATTRIBUTE?FUNCTION NAME?MODULE NAME SEGM CODE

?PR?INITIAL?DS1302 SEGMENT CODE

PUBLIC INITIAL ;SERVE TO EXTERN.

RSEG ?PR?INITIAL?DS1302

USING 0

INITIAL:

CLR CS ;DISABLE->CLEAR CS

CLR SCL ;WHEN CS BE HIGH SCL MUST BE LOW

CLR SDA ;END INITIAL

RET

;**************************************

;--S-DATA INPUT: DS1302 with Assembly L

;--Programer : MicroAC

;--Parameter : R7,R5

;--Date : 2012.03.10

;--NOTE: WRITE COMMAND FIRST AND THEN IN

;**************************************

?PR?_Ds1302DatIn?DS1302 SEGMENT CODE

PUBLIC _Ds1302DatIn ;SERVE TO EXTERN.

RSEG ?PR?_Ds1302DatIn?DS1302

USING 0

_Ds1302DatIn:

MOV A ,#01H

ANL A ,R5 ;GET FLAG.

CLR C

RRC A

MOV FLAG,C

SETB CS ;START-> ENABLE - > HIGH

MOV A,R7 ;COMMAND

CLR C

MOV R6,#8 ;EIGHT CIRCLE.

WDAT_LOOP:

RLC A ;MSB WILL BE TRANSFER FIRSTLY.

MOV SDA,C ;TRANSFER BIT DATA

SETB SCL ;RISING EDGE.

CLR C ;RESET C REGISTER.

CLR SCL ;FALLING EDGE.

DJNZ R6,WDAT_LOOP

JBC FLAG,IN_EXIT

CLR CS ;STOP

IN_EXIT:

RET

;**************************************

;--DATA OUTPUT : DS1302 with Assembly L

;--Programer : MicroAC

;--Parameter : FLAG DETERMIN EN OR DISABLE

;--Date : 2012.03.10

;--NOTE: READ COMMAND FIRST AND THEN OUT

;**************************************

?PR?_Ds1302DatRed?DS1302 SEGMENT CODE

PUBLIC _Ds1302DatRed ;SERVE TO EXTERN.

RSEG ?PR?_Ds1302DatRed?DS1302

USING 0

_Ds1302DatRed:

MOV A ,#01H

ANL A ,R7 ;GET FLAG.

CLR C

RRC A

MOV FLAG,C

CLR C

CLR A

SETB SCL ;RISING EDGE.

MOV R6,#8 ;EIGHT CIRCLE.

RDAT_LOOP:

CLR SCL ;FALLING EDGE.

MOV C,SDA ;TRANSFER BIT DATA

SETB SCL ;RISING EDGE.

RLC A ;MSB WILL BE TRANSFER FIRSTLY.

CLR C ;RESET C REGISTER.

DJNZ R6,RDAT_LOOP

JBC FLAG,OUT_EXIT

CLR CS ;STOP

MOV R7,A ;RETURN DATA YOU READ.

OUT_EXIT:

RET

END

//C语言源程序

#include"1602.h"//这个是用户自定义头文件

extern void INITIAL(void);

//command OR data/add will be transfered,AND SECOND IS EN OR DISABLE FALG .

//FLAG IS 1 WILL CONTINUTE.0 WILL STOP WRITE.

extern void Ds1302DatIn(unsigned char DAT ,unsigned char FLAG);

extern unsigned char Ds1302DatRed(unsigned char FLAG);

unsigned char dis[]="0123456789-";

unsigned char code time[]="10:20:50";

void main()

{

LCDInit();

INITIAL();

DisplayListChar(0,0,time);

while(1)

{

// Ds1302DatIn(0xff,1);

// Ds1302DatRed(1);

}