Philips Semiconductors

Preliminary specification

83C453/87C453

80C51 8-bit microcontroller family

8K/256 OTP/ROM, expanded I/O

1998 Apr 23

8

PX0

LSB

MSB

BIT

SYMBOL

FUNCTION

IP.7

—

Reserved.

IP.6

POB

Defines the Output Buffer Full interrupt (IOB) priority level. POB=1 programs it to the higher priority level.

IP.5

PIB

Defines the Input Buffer Full interrupt (IIB) priority level. PIB=1 programs it to the higher priority level.

IP.4

PS

Defines the Serial Port interrupt priority level. PS=1 programs it to the higher priority level.

IP.3

PT1

Defines the Timer 1 interrupt priority level. PT1=1 programs it to the higher priority level.

IP.2

PX1

Defines the External Interrupt 1 priority level. PX1=1 programs it to the higher priority level.

IP.1

PT0

Enables or disables the Timer 0 interrupt priority level. PT0=1 programs it to the higher priority level.

IP.0

PX0

Defines the External Interrupt 0 priority level. PX0=1 programs it to the higher priority level.

SU00564

PT0

PX1

PT1

PS

PIB

POB

—

Figure 3. 8XC453 Interrupt Priority (IP) Register

IDL

PCON (87H)

BIT

SYMBOL

FUNCTION

PCON.7

SMOD1

Double Baud rate bit. When set to a 1 and Timer 1 is used to generate baud rate, and the Serial Port

is used in modes 1, 2, or 3.

PCON.6

SMOD0

If set to 1, SCON.7 will be the Framing Error bit (FE). If PCON.6 is cleared, SCON.7 will be SM0.

PCON.5

—

Reserved.

PCON.4

POF

if a warm start has occurred.

PCON.3

GF1

General-purpose flag bit.

PCON.2

GF0

General-purpose flag bit.

PCON.1

PD

Power-Down bit. Setting this bit activates power-down mode. It can only be set if input EW is high.

PCON.0

IDL

Idle mode bit. Setting this bit activates the idle mode.

If logic 1s are written to PD and IDL at the same time, PD takes precedence.

SU00565

PD

GF0

GF1

POF

—

SMOD2

SMOD1

0

1

2

3

4

5

6

7

Figure 4. Power Control Register (PCON)

Table 2. Interrupt Table

POLLING

PRIORITY

SOURCE

REQUEST

BITS/FLAG

VECTOR

ADDRESS

1

INTO

IE0

03H highest priority

2

Timer0

TF0

0BH

3

INT1

IE1

13H

4

Timer1

TF1

1BH

5

Port 6

OBF

33H

6

Serial I/O

RI,TI

23H

7

Port 6

IBF

2BH lowest priority