as done through it by hardware. In other words, interrupts or pending interrupts can be generated or
canceled in software.
The following content describes several SFR related to interrupt mechanism.
SFR: IE (Interrupt Enabling):
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
EA
ET2
ES
ET1
EX1
ET0
EX0
EA: Global disables all interrupts when cleared.
ET2: When set, enables Timer2 interrupt.
ES:
When set, enables the serial port interrupt.
ET1: When set, enables Timer1 interrupt.
EX1: When set, enables external interrupt 1.
ET0: When set, enables Timer 0 interrupt.
EX0: When set, enables external interrupt 0.
SFR: IP (Interrupt Priority Low):
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
-
-
PT2
PS
PT1
PX1
PT0
PX0
PT2: If set, Set priority for timer2 interrupt higher
PS: If set, Set priority for serial port interrupt higher
PT1: If set, Set priority for timer1 interrupt higher
PX1: If set, Set priority for external interrupt 1 higher
PT0: If set, Set priority for timer0 interrupt higher
PX0: If set, Set priority for external interrupt 0 higher
SFR: IPH (Interrupt Priority High):
Bit-7
Bit-6
Bit-5
Bit-4
Bit-3
Bit-2
Bit-1
Bit-0
PX3H
PX2H
PT2H
PSH
PT1H
PX1H
PT0H
PX0H
PX3H: If set, Set priority for external interrupt 3 highest
PX2H: If set, Set priority for external interrupt 2 highest
PT2H: If set, Set priority for timer2 interrupt highest
PSH:
If set, Set priority for serial port interrupt highest
PT1H: If set, Set priority for timer1 interrupt highest
PX1H: If set, Set priority for external interrupt 1 highest
PT0H: If set, Set priority for timer0 interrupt highest
PX0H: If set, Set priority for external interrupt 0 highest
MEGAWIN
MPC89x515A Data Sheet
21