2–21

2.9.1

8052 Standard Interrupt Enable Register

7

6

5

4

3

210

EA

RSV

ET2

ES

ET1

EX1

ET0

INT0

R/W

R/O

R/O

R/W

R/W

R/W

R/W

R/W

BIT

NAME

RESET

FUNCTION

0

INT0

0

Enable or disable external interrupt-0

EX0 = 0

External interrupt-0 is disabled.

EX0 = 1

External interrupt-0 is enabled.

1

ET0

0

Enable or disable timer-0 interrupt

ET0 = 0

Timer-0 interrupt is disabled.

ET0 = 1

Timer-0 interrupt is enabled.

2

EX1

0

Enable or disable external interrupt-1

EX1 = 0

External interrupt-1 is disabled.

EX1 = 1

External interrupt-1 is enabled.

3

ET1

0

Enable or disable timer-1 interrupt

ET1 = 0

Timer-1 interrupt is disabled.

ET1 = 1

Timer-1 interrupt is enabled.

4

ES

0

Enable or disable serial port interrupts

ES = 0

Serial port interrupt is disabled.

ES = 1

Serial port interrupt is enabled.

5

ET2

0

Enable or disable timer-2 interrupt

ET2 = 0

Timer-2 interrupt is disabled.

ET2 = 1

Timer-2 interrupt is enabled.

6

RSV

0

Reserved

7

EA

0

Enable or disable all interrupts (global disable)

EA = 0

Disable all interrupts.

EA = 1

Each interrupt source is individually controlled.

2.9.2

Additional Interrupt Sources

noted that the external INT0 and INT1 are not used. Furthermore, INT0 must be programmed as an active-low level

interrupt (not edge-triggered). A vector interrupt register is provided to identify all interrupt sources (see vector

interrupt register definition, Section 2.9.3). Up to 64 interrupt vectors are provided. It is the responsibility of the MCU

to read the vector and dispatch the proper interrupt routine.