;gg104.asm
;for <4.>產生1s方波<芯片8253-5>
;2005-05
;lcy/p_Sa
data	SEGMENT
        T0	EQU	280h
        T1	EQU	281h
        T2	EQU	282h
        TCTL	EQU	283h
data	ENDS
stack0 SEGMENT para stack
        DW	20h	DUP(0)
stack0 ENDS
        
coseg	SEGMENT
        ASSUME CS:coseg,DS:data,SS:stack0
start:  MOV AX, data
        MOV DS, AX
;================MOV-DS-AX==============  
        MOV DX, TCTL
        MOV AL, 25h	;00-10-010-1B:0通道，高8位，方式2（頻率發生器），BCD記數
        OUT DX, AL
        MOV DX, T0
        MOV AL, 10h	;1us=>1ms脈沖
        OUT DX, AL
        MOV DX, TCTL
        MOV AL, 67h	;01-10-011-1B:1通道，高8位，方式3（方波發生器），BCD記數
        OUT DX, AL
        MOV DX, T1
        MOV AL, 10h	;1ms=>1s方波
        OUT DX, AL
;================INT-21H================
        MOV AH, 4ch
        INT 21h
coseg	ENDS
        END	start