| 74HC595具有一個(gè)8位串行輸入并行輸出的移位寄存器和一個(gè)8位輸出鎖存器。
;================================================
;74HC595 走馬燈演示程序 ;創(chuàng)作日期：2007/08/012
;創(chuàng)作者： 給我一支煙
;================================================ SDATA_595 EQU P1.0 ;串行數(shù)據(jù)輸入
SCLK_595 EQU P1.1 ;移位時(shí)鐘脈沖
RCK_595 EQU P1.2 ;輸出鎖存器控制脈沖
;================================================ ORG 0000H
LJMP MAIN
ORG 0030H ;================================================
MAIN:
MOV SP,#60H
MOV R0,#0FEH
MAIN1:
CALL OUT_595
CALL DELAY
MOV A,R0
RL A
MOV R0,A
JMP MAIN1
;---------------------------------------------------------------
;輸出鎖存器輸出數(shù)據(jù)子程序
;---------------------------------------------------------------
OUT_595:
LCALL WR_595
CLR RCK_595
NOP
NOP
SETB RCK_595 ;上升沿將數(shù)據(jù)送到輸出鎖存器
NOP
NOP
NOP
CLR RCK_595
RET
;--------------------------------------------------------------
;移位寄存器接收數(shù)據(jù)子程序
;--------------------------------------------------------------
WR_595:
MOV R4,#08H
MOV A,R0
WR_LOOP:
RLC A
MOV SDATA_595,C
SETB SCLK_595 ;上升沿發(fā)生移位
NOP
NOP
CLR SCLK_595
DJNZ R4,WR_LOOP
RET
;--------------------------------------------------------------
;延時(shí)子程序
;--------------------------------------------------------------
DELAY:
MOV R5,#03H
DEL0:
MOV R6,#0FFH
DEL1:
MOV R7,#0FFH
DJNZ R7,$
DJNZ R6,DEL1
DJNZ R5,DEL0
RET
;---------------------------------------------------------------
END |
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