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Real-Time Clock. Module M19.4 Section 14.1 (p.415). Real-time Clock. Time of Day options using INT 1AH. 32-bit counter at address 0040:006C - 0040:006F Counter increments 18.2 times per second. Each increment is called a tick. Interrupt Vector Table. INT 1CH Timer Tick Offset: $070.

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Real time clock

Real-Time Clock

Module M19.4

Section 14.1 (p.415)


Real time clock1
Real-time Clock

Time of Day options using INT 1AH

32-bit counter at address 0040:006C - 0040:006F

Counter increments 18.2 times per second.

Each increment is called a tick.


Interrupt

Vector

Table

INT 1CH

Timer Tick

Offset: $070


The Timer Tick hardware interrupt increments the

32-bit counter and then calls INT 1CH.

The software interrupt routine just returns using

the IRET instruction.

Therefore, INT 1CH is called 18.2 times per second.


Interrupt

Vector

Table

INT 1CH

Timer Tick

Offset: $070

You can replace the

IP and CS values at

0000:0070 with the

address of your routine.


Real time clock interrupt service routine algorithm
Real-time clock interrupt service routine algorithm


Setting the interrupt vector using an int 21h dos call
Setting the interrupt vectorusing an INT 21H DOS call

push ds

push cs

pop ds

mov dx,offset intser

mov al,1Ch

mov ah,25h

int 21h

pop ds


Storing the time 10 24 37 in the keyboard buffer
Storing the time 10:24:37in the keyboard buffer


Real time clock interrupt service routine algorithm1
Real-time clock interrupt service routine algorithm


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