Intel 80C186XL User Manual page 248

lib_80186 segment public 'code'
assume cs:lib_80186, ds:data
public _set_time
_set_time proc far
push bp
mov bp, sp
hour equ word ptr[bp+6]
minute equ word ptr[bp+8]
second equ word ptr[bp+10]
T2Compare equ word ptr[bp+12]
push ax
push dx
push si
push ds
xor ax, ax
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
mov _hour, al
mov ax, minute
mov _minute, al
mov ax, second
mov _second, al
mov _msec, 0
mov dx, T2CNT
xor ax, ax
out dx, al
mov dx, T2CMPA
mov ax, T2Compare
out dx, al
mov dx, T2CON
mov ax, 0E001H
out dx, al
mov dx, TCUCON
xor ax, ax
out dx, al
Example 9-1. Configuring a Real-Time Clock (Continued)
;save caller's bp
;get current top of stack
;get parameters off stack
;save registers used
;set interrupt vector
;set time
;clear Count register
;set maximum count value
;see note in header above
;set up the control word:
;enable counting,
;generate interrupt on MC,
;continuous counting
;set up interrupt controller
;unmask highest priority interrupt
TIMER/COUNTER UNIT
9-19