Intel 8XC196NP User Manual page 109

8XC196NP, 80C196NU USER'S MANUAL
Interrupt Pending or PTSSRV Bit Set
Highest Priority PTS Interrupt
Return
Figure 6-1. Flow Diagram for PTS and Standard Interrupts
6-2
NMI
Yes
Pending
?
No
No
INT_MASK. x
= 1?
Yes
PTS
No
Enabled?
Yes
No
PTSSEL. x
Bit = 1?
Yes
Priority
Encoder
Reset INT_PEND. x
Bit
Reset PTSSRV. x
Execute 1 PTS Cycle
(Microcoded)
Decrement
PTSCOUNT
No
PTSCOUNT
= 0?
Yes
Clear PTSSEL. x Bit
Set PTSSRV. x Bit
Return
Return
No
Interrupts
Enabled
?
Yes
Priority
Encoder
Highest Priority Interrupt
Yes No
PTSSRV. x
= 1?
Reset INT_PEND. x
Bit
PUSH PC
on Stack
LJMP to
ISR
Execute Interrupt
Service Routine
POP PC
from Stack
Return
Return
Bit
A0320-02