IBM uPD78082 User Manual

Page 208

185

CHAPTER 12 INTERRUPT FUNCTION

Figure 12-11. Interrupt Request Acknowledge Processing Algorithm

Start

Ч Ч

IF=1?

Ч Ч

MK=0?

Ч Ч

PR=0?

Any

Simultaneously

generated

××

PR=0 interrupt

requests?

Any

Simultaneously

generated high-priority

interrupt requests?

IE=1?

ISP=1?

Vectored interrupt
servicing

Interrupt request
reserve

Vectored interrupt
servicing

IE=1?

Yes (High priority)

Yes

Yes (Interrupt Request
Generation)

Yes

No (Low Priority)

Yes

Do any

of the simultaneously

generated

××

PR=0 interrupt

requests have a high

priority?

××

: Interrupt request flag

××

MK : Interrupt mask flag

××

PR : Priority specify flag

: Flag which controls maskable interrupt request acknowledgment (1 = enable, 0 = disable)

ISP

: Flag which indicates the priority of the interrupt currently being processed. (0 = high priority

interrupt being processed, 1= interrupt request not acknowledged, or low priority interrupt

being processed.)

This manual is related to the following products:

uPD78081 uPD78P083