80C51 Datasheet, PDF (18/38 Pages) NXP Semiconductors – 80C51 8-bit microcontroller family 4K/128 OTP/ROM/ROMless low voltage 2.7V.5.5V, low power, high speed 33 MHz

Philips Semiconductors
80C51 8-bit microcontroller family
4K/128 OTP/ROM/ROMless, low voltage (2.7V–5.5V),
low power, high speed (33 MHz)
Product specification
80C51/87C51/80C31
IP (0B8H)
7
6
5
4
3
2
—
—
PT2
PS
PT1 PX1
Priority Bit = 1 assigns higher priority
Priority Bit = 0 assigns lower priority
BIT
SYMBOL FUNCTION
IP.7
—
Not implemented, reserved for future use.
IP.6
—
Not implemented, reserved for future use.
IP.5
PT2
Timer 2 interrupt priority bit.
IP.4
PS
Serial Port interrupt priority bit.
IP.3
PT1
Timer 1 interrupt priority bit.
IP.2
PX1
External interrupt 1 priority bit.
IP.1
PT0
Timer 0 interrupt priority bit.
IP.0
PX0
External interrupt 0 priority bit.
Figure 11. IP Registers
1
0
PT0 PX0
SU00572
IPH (B7H)
7
6
5
4
3
2
1
0
—
— PT2H PSH PT1H PX1H PT0H PX0H
BIT
IPH.7
IPH.6
IPH.5
IPH.4
IPH.3
IPH.2
IPH.1
IPH.0
Priority Bit = 1 assigns higher priority
Priority Bit = 0 assigns lower priority
SYMBOL
—
—
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
FUNCTION
Not implemented, reserved for future use.
Not implemented, reserved for future use.
Timer 2 interrupt priority bit high.
Serial Port interrupt priority bit high.
Timer 1 interrupt priority bit high.
External interrupt 1 priority bit high.
Timer 0 interrupt priority bit high.
External interrupt 0 priority bit high.
Figure 12. IPH Registers
SU01058
2000 Jan 20
18