Intel 80C188XL, 80C186XL user manual Timer/Counter Unit

		TIMER/COUNTER UNIT
_CMPB	equ word ptr[bp+6]	;get parameter off the stack
push	ax	;save registers that will be
push	dx	;modified
mov	dx, T1CNT	;Clear Timer 1 Counter
xor	ax, ax
out	dx, al
mov	dx, T1CMPA	;set time before t_shot to 0
mov	ax, 1
out	dx, al
mov	dx, T1CMPB	;set pulse time
mov	ax, _CMPB
out	dx, al
mov	dx, T1CON
mov	ax, C002H	;start Timer 1
out	dx, al
CountDown:	in ax, dx	;read in T1CON
test	ax, MaxCount	;max count occurred?
jz	CountDown	;no: then wait
and	ax, not MaxCount	;clear max count bit
out	dx, al	;update T1CON
pop	dx	;restore saved registers
pop	ax
pop	bp	;restore caller’s bp
ret
_one_shot	endp
lib_80186	ends
end

Example 9-3. Configuring a Digital One-Shot (Continued)

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