impact as done through 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
EA
EA:
Bit-6
Bit-5
ET2
Bit-4
ES
Bit-3
ET1
Bit-2
EX1
Bit-1
ET0
Bit-0
EX0
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
-
PT2:
PS:
PT1:
PX1:
PT0:
PX0:
Bit-6
-
Bit-5
PT2
Bit-4
PS
Bit-3
PT1
Bit-2
PX1
Bit-1
PT0
Bit-0
PX0
If set, Set priority for timer2 interrupt higher
If set, Set priority for serial port interrupt higher
If set, Set priority for timer1 interrupt higher
If set, Set priority for external interrupt 1 higher
If set, Set priority for timer0 interrupt higher
If set, Set priority for external interrupt 0 higher
SFR:
IPH
(Interrupt
Priority High):
Bit-7
PX3H
PX3H:
PX2H:
PT2H:
PSH:
PT1H:
PX1H:
PT0H:
PX0H:
Bit-6
PX2H
Bit-5
PT2H
Bit-4
PSH
Bit-3
PT1H
Bit-2
PX1H
Bit-1
PT0H
Bit-0
PX0H
If set, Set priority for external interrupt 3 highest
If set, Set priority for external interrupt 2 highest
If set, Set priority for timer2 interrupt highest
If set, Set priority for serial port interrupt highest
If set, Set priority for timer1 interrupt highest
If set, Set priority for external interrupt 1 highest
If set, Set priority for timer0 interrupt highest
If set, Set priority for external interrupt 0 highest
MEGAWIN
MPC89x54A Data Sheet
21
MEGAWIN [ MEGAWIN TECHNOLOGY CO., LTD ]
