W78C438C

- 10 -

BIT

ADDR.

NAME

FUNCTION

7

0C7H

PX3

software.

6

0C6H

EX3

5

0C5H

IE3

If IT3 is "1," IE3 is set/cleared automatically by hardware when interrupt is

detected/serviced.

4

0C4H

IT3

INT3

is falling-edge/low-level triggered when this bit is set/cleared by

software.

3

0C3H

PX2

software.

2

0C2H

EX2

1

0C1H

IE2

If IT2 is "1," IE2 is set/cleared automatically by hardware when interrupt is

detected/serviced.

0

0C0H

IT2

INT2

is falling-edge/low-level triggered when this bit is set/cleared by

software.

Table 2. Functions of XICON Register

INTERRUPT SOURCE

VECTOR ADDRESS

PRIORITY SEQUENCE

External Interrupt 0

03H

0 (Highest)

Timer/Counter 0

0BH

1

External Interrupt 1

13H

2

Timer/Counter 1

1BH

3

Serial Port

23H

4

Timer/Counter 2

2BH

5

External Interrupt 2

33H

6

External Interrupt 3

3BH

7 (Lowest)

Table 3. Priority of Interrupts