Epa Interrupt Priority Vector Register; Epa Interrupt Priority Vectors - Intel 87C196CA Supplement To User’s Manual

8XC196L X SUPPLEMENT
7.1.3

EPA Interrupt Priority Vector Register

Figure 7-7 illustrates the EPA interrupt priority vector (EPAIPV) register for the 8XC196Lx mi-
crocontroller family.
EPAIPV
When an EPA x interrupt occurs, the EPA interrupt priority vector (EPAIPV) register contains a number
that identifies the highest priority, active, multiplexed interrupt source (see Table 7-2).
EPAIPV allows software to branch via the TIJMP instruction to the correct interrupt service routine
when EPA x is activated. Reading EPAIPV clears the EPA pending bit for the interrupt associated with
the value in EPAIPV. When all the EPA pending bits are cleared, the EPA x pending bit is also cleared.
7
— —
Bit Bit
Number Mnemonic
5:7 —
4:0 PV4:0
Figure 7-7. EPA Interrupt Priority Vector Register (EPAIPV)
Value Interrupt
14H
13H
12H
11H
10H
0FH
0EH
†
87C196LA, LB only; reserved on 83C196LD.
7-6
— PV4
Reserved; for compatibility with future devices, write zeros to these bits.
Priority Vector
These bits contain a number from 01H to 14H corresponding to the
highest-priority active interrupt source. This value, when used with the
TIJMP instruction, allows software to branch to the correct interrupt
service routine.
Table 7-2. EPA Interrupt Priority Vectors
Value
— 0DH
— 0CH
EPA6 0BH
EPA7 0AH
EPA8 09H
EPA9 08H
OVR0 07H
PV3 PV2
Function
Interrupt Value
OVR1 06H
OVR2 05H
OVR3 04H
— 03H
— 02H
— 01H
— 00H
Address: 1FA8H
Reset State: 00H
0
PV1 PV0
Interrupt
OVR8
OVR9
†
COMP0
†
COMP1
OVRTM1
OVRTM2
None