Minimum Mode Interface
Each and every group is explained clearly.
Address/Data Bus:
Status signal:
Control Signals:
Interrupt signals:
DMA Interface signals:
Maximum Mode Interface
8288 Bus Controller – Bus Command and Control Signals:
Bus busy (BUSY), common bus request (CBRQ), bus priority out (BPRO), bus priority in (BPRN), bus request (BREQ) and bus clock (BCLK).
QS1 | QS0 | Queue Status |
0 (Low) | 0 | Queue Empty. The queue has been reinitiated as a result of the execution of a transfer instruction. |
0 | 1 | First Byte. The byte taken from the queue was the first byte of the instruction. |
1 | 0 | Queue Empty. The queue has been reinitiated as a result of the execution of a transfer instruction. |
1 | 1 (High) | Subsequent Byte. The byte taken from the queue was the subsequent byte of the instruction. |
Interrupts
Definition: The meaning of ‘interrupts’ is to break the sequence of operation. While the CPU is executing a program, on ‘interrupt’ breaks the normal sequence of execution of instructions, diverts its execution to some other program called Interrupt Service Routine (ISR).After executing ISR , the control is transferred back again to the main program.
Interrupt processing is an alternative to polling.
Need for Interrupt: Interrupts are particularly useful when interfacing I/O devices that provide or require data at relatively low data transfer rate.
Types of Interrupts: There are two types of Interrupts in 8086. They are:
(i) Hardware Interrupts and
(ii) Software Interrupts
(i) Hardware Interrupts (External Interrupts). The Intel microprocessors support hardware interrupts through:
INTR. INTR and NMI
(ii) Software Interrupts (Internal Interrupts and Instructions) .Software interrupts can be caused by:
Performance of Software Interrupts
Interrupt Vector Table
Functions associated with INT00 to INT04
INT 00 (divide error)
INT 01
INT 02 (Non maskable Interrupt)
INT 03 (break point)
INT 04 (Signed number overflow)
Performance of Hardware Interrupts
Interrupt Priority Structure
1. What is the minimum mode in computer programming? |
2. How does the minimum mode differ from the maximum mode in computer programming? |
3. What is the maximum mode in computer programming? |
4. What are the advantages of using the minimum mode in computer programming? |
5. What are the advantages of using the maximum mode in computer programming? |
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