8XC196LX SUPPLEMENT

7.1.3EPA Interrupt Priority Vector Register

Figure 7-7 illustrates the EPA interrupt priority vector (EPAIPV) register for the 8XC196Lx mi- crocontroller family.

EPAIPV

Address:

1FA8H

 

Reset State:

00H

When an EPAx 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 EPAx 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 EPAx pending bit is also cleared.

7

 

 

 

 

 

 

 

 

 

0

 

PV4

 

PV3

 

PV2

PV1

PV0

 

 

 

 

 

 

 

 

 

 

 

Bit

Bit

 

 

 

 

Function

 

 

Number

Mnemonic

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5:7

Reserved; for compatibility with future devices, write zeros to these bits.

 

 

 

 

 

 

 

 

 

4:0

PV4:0

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.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 7-7. EPA Interrupt Priority Vector Register (EPAIPV)

Table 7-2. EPA Interrupt Priority Vectors

Value

Interrupt

 

 

14H

 

 

13H

 

 

12H

EPA6

 

 

11H

EPA7

 

 

10H

EPA8

 

 

0FH

EPA9

 

 

0EH

OVR0

 

 

Value

Interrupt

 

Value

Interrupt

 

 

 

 

 

0DH

OVR1

 

06H

OVR8

 

 

 

 

 

0CH

OVR2

 

05H

OVR9

 

 

 

 

 

0BH

OVR3

 

04H

COMP0

0AH

 

03H

COMP1

09H

 

02H

OVRTM1

 

 

 

 

 

08H

 

01H

OVRTM2

 

 

 

 

 

07H

 

00H

None

 

 

 

 

 

87C196LA, LB only; reserved on 83C196LD.

7-6

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Intel 8XC196Jx, 8XC196Lx, 8XC196Kx, 87C196CA user manual EPA Interrupt Priority Vector Register, Value Interrupt, Epaipv