TS80C51RA2 Atmel Corporation, TS80C51RA2 Datasheet - Page 40

• Manufacturer Part Number: TS80C51RA2
• Description: High Performance 8-bit Microcontroller
• Manufacturer: Atmel Corporation

40
TS8xC51Rx2
Table 20. Priority Level Bit Values
A low-priority interrupt can be interrupted by a high priority interrupt, but not by another
low-priority interrupt. A high-priority interrupt can’t be interrupted by any other interrupt
source.
If two interrupt requests of different priority levels are received simultaneously, the
request of higher priority level is serviced. If interrupt requests of the same priority level
are received simultaneously, an internal polling sequence determines which request is
serviced. Thus within each priority level there is a second priority structure determined
by the polling sequence.
Table 21. IE Register
IE - Interrupt Enable Register (A8h)
Reset Value = 0000 0000b
Bit addressable
Number
IPH.x
Bit
EA
7
0
0
1
1
7
6
5
4
3
2
1
0
Mnemonic
EC
6
IP.x
EX1
EX0
ET2
ET1
ET0
Bit
EA
EC
ES
0
1
0
1
ET2
5
Description
Enable All interrupt bit
Clear to disable all interrupts.
Set to enable all interrupts.
If EA=1, each interrupt source is individually enabled or disabled by setting
or clearing its own interrupt enable bit.
PCA interrupt enable bit
Clear to disable . Set to enable.
Timer 2 overflow interrupt Enable bit
Clear to disable timer 2 overflow interrupt.
Set to enable timer 2 overflow interrupt.
Serial port Enable bit
Clear to disable serial port interrupt.
Set to enable serial port interrupt.
Timer 1 overflow interrupt Enable bit
Clear to disable timer 1 overflow interrupt.
Set to enable timer 1 overflow interrupt.
External interrupt 1 Enable bit
Clear to disable external interrupt 1.
Set to enable external interrupt 1.
Timer 0 overflow interrupt Enable bit
Clear to disable timer 0 overflow interrupt.
Set to enable timer 0 overflow interrupt.
External interrupt 0 Enable bit
Clear to disable external interrupt 0.
Set to enable external interrupt 0.
ES
4
Interrupt Level Priority
ET1
3
3 (Highest)
0 (Lowest)
1
2
EX1
2
ET0
1
4188A–8051–10/02
EX0
0