Dear all,
I have gone through 80188XL ICU part
I am pretty clear with master mode.But in slave mode i have the following quries:
1.Why this interrupt vector register is added?What is the use of making the last two bits of
interrupt vector register as programmable,since to clear the in- service bit,write the three
least significant bits of interrupt type(fixed)which are same as in master mode?
2.It is mentioned that, the external 8259A determines which slave interrupt controller has
the highest priority interrupt request.However,the ICU process only the internal interrupt
request.This means ICU itself determine the priority in slave mode also..Then how external
8259A act as a master?I guess it will determine the priority between its external interrupts
and internal interrupts of ICU.It is not clearly mentioned in the manual.
It would have been better if they have given an example for slave mode also....
pls clarify the above doubts...
Thanks in advance....
regards, fazal