The 8259 can receive ICWs in the sequence ICW1, ICW2, ICW3, ICW4 or ICW1, ICW2, ICW4....

50.1K

Verified Solution

Question

Electrical Engineering

The 8259 can receive ICWs in the sequence ICW1, ICW2, ICW3, ICW4or ICW1, ICW2, ICW4. How does it know which option is beingprogrammed?

Answer & Explanation Solved by verified expert

3.6 Ratings (506 Votes)

InitializationControl Word 2 ICW2After issuing ICW1 on even address the PIC is ready to acceptinitialization Control Word 2 It is issued to an address havingA01 ie on odd address The format for ICW2 is shown belowD7 D6 D5 D4 D3 D2 D1 D0A15T2 A14T6 A13T5 A12T4 A11T3 A10 A9 A8A15A8 specify the higher byte address of the interrupt for808085 system only For 8086 T7T3 are used to specify theinterrupt vector type These bits are inserted in the five mostsignificant bits of the vectoring byte and the 8259A sets the threeleast significant bits according to the interrupt level asbelowThus an 8085A system using a single 8259A could be programmedwith only two ICWs ICW1 ICW2For example let ICW1 0001 00100 2 andICW2 0000 0100 2With these See Answer

Get Answers to Unlimited Questions

Join us to gain access to millions of questions and expert answers. Enjoy exclusive benefits tailored just for you!

Membership Benefits:

Unlimited Question Access with detailed Answers
Zin AI - 3 Million Words
10 Dall-E 3 Images
20 Plot Generations
Conversation with Dialogue Memory
No Ads, Ever!
Access to Our Best AI Platform: Flex AI - Your personal assistant for all your inquiries!

Become a Member