Intel 8253 - Symbol Function

Philips Semiconductors Product specification
80C31/80C32
80C51 8-bit microcontroller family
128/256 byte RAM ROMless low voltage (2.7V–5.5V),
low power, high speed (33 MHz)
2000 Aug 07
18
PX0IP (0B8H)
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.
SU00572
PT0PX1PT1PSPT2——
01234567
Figure 11. IP Registers
PX0HIPH (B7H)
Priority Bit = 1 assigns higher priority
Priority Bit = 0 assigns lower priority
BIT SYMBOL FUNCTION
IPH.7 — Not implemented, reserved for future use.
IPH.6 — Not implemented, reserved for future use.
IPH.5 PT2H Timer 2 interrupt priority bit high.
IPH.4 PSH Serial Port interrupt priority bit high.
IPH.3 PT1H Timer 1 interrupt priority bit high.
IPH.2 PX1H External interrupt 1 priority bit high.
IPH.1 PT0H Timer 0 interrupt priority bit high.
IPH.0 PX0H External interrupt 0 priority bit high.
SU01058
PT0HPX1HPT1HPSHPT2H——
01234567
Figure 12. IPH Registers