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4428E–8051–02/08
AT/TS80C31X2
10. Interrupt System
The TS80C31X2 has a total of 5 interrupt vectors: two external interrupts (INT0 and INT1), two
timer interrupts (timers 0 and 1) and the serial port interrupt. These interrupts are shown in
Fig-Figure 10-1. Interrupt Control System
Each of the interrupt sources can be individually enabled or disabled by setting or clearing a bit
disable bit, which must be cleared to disable all interrupts at once.
Each interrupt source can also be individually programmed to one out of four priority levels by
setting or clearing a bit in the Interrupt Priority register (See
Table 10-3.) and in the Interrupt Pri-
ority High register (See
Table 10-4.). shows the bit values and priority levels associated with
each combination.
Table 10-1.
Priority Level Bit Values
IE1
0
3
High priority
interrupt
Interrupt
polling
sequence, decreasing
from high to low priority
Low priority
interrupt
Global Disable
Individual Enable
TI
RI
TF0
INT0
INT1
TF1
IPH, IP
IE0
0
3
0
3
0
3
0
3
IPH.x
IP.x
Interrupt Level Priority
0
0 (Lowest)
0
1
0
2
1
3 (Highest)