Intel 80C188XL, 80C186XL user manual Out Dx, al

TIMER/COUNTER UNIT

lib_80186 segment public ’code’ assume cs:lib_80186, ds:data

public _set_time

_set_time proc far

push	bp	;save caller’s bp
mov	bp, sp	;get current top of stack
hour	equ word ptr[bp+6]	;get parameters off stack
minute	equ word ptr[bp+8]
second	equ word ptr[bp+10]
T2Compare equ word ptr[bp+12]
push	ax	;save registers used
push	dx
push	si
push	ds
xor	ax, ax	;set interrupt vector
mov	ds, ax
mov	si, 4*timer_2_int
mov	word ptr ds:[si], offset
timer_2_interrupt_routine
inc	si
inc	si
mov	ds:[si], cs
pop	ds
mov	ax, hour	;set time
mov	_hour, al
mov	ax, minute
mov	_minute, al
mov	ax, second
mov	_second, al
mov	_msec, 0
mov	dx, T2CNT	;clear Count register
xor	ax, ax
out	dx, al
mov	dx, T2CMPA	;set maximum count value
mov	ax, T2Compare	;see note in header above
out	dx, al
mov	dx, T2CON	;set up the control word:
mov	ax, 0E001H	;enable counting,
out	dx, al	;generate interrupt on MC,
		;continuous counting
mov	dx, TCUCON	;set up interrupt controller
xor	ax, ax	;unmask highest priority interrupt
out	dx, al

Example 9-1. Configuring a Real-Time Clock (Continued)

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