- 8259 microprocessor can be programmed according to given interrupts condition and it can be provided either with level or edge triggered interrupt level.
- It can be programmed either work in 8085 or in 8086 microprocessors.
- Individual interrupt bits can be masked.
- By conducting more number of 8259 we can get upto 64 interrupt pins.
It contains 3 rigisters commonly known as ISR, IRR, IMR & there is 1 priority resolver (PR).
- Interrupt Request Register (IRR): It stores those bits which are requesting for their interrupt services.
- Interrupt Service Register (ISR): It stores that interrupt levels which is currently being servied.
- Interrupt Mask Register (IMR): It stores that interrupt levels which have to be masked. These interrupts levels are already acccepted by 8259 microprocessor.
Priority Resolver (PR): It examines all the 3 registers and set the priority of interrupts and set the interrupt levels in ISR which has highest priority and rest the interrupt bit is IRR which is already accepted.
SP/EN (low active pin): If its value is 1 it works in master mode & if its value=e is 0 then it works in slave mode.
Cascade Buffer: It is used to cascade more number of Programmable Interrupt Controller to increase the interrupts handling capability upto 64 level.
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- Pin diagram of 8086 microprocessor
- Timing diagram of MOV Instruction in Microprocessor
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- Pipelined architecture with its diagram
- Pin diagram of 8051 Microcontroller
- 8255 microprocessor operating modes
- Interrupts in 8085 microprocessor
- Registers of 8085 microprocessor
- Flag register in 8085 microprocessor
- Instruction cycle in 8085 microprocessor
- Flag register of 8086 microprocessor
- Arithmetic instructions in 8085 microprocessor
- Logical instructions in 8085 microprocessor
- Data transfer instructions in 8085 microprocessor
- General purpose registers in 8086 microprocessor
- Branching instructions in 8085 microprocessor
- Arithmetic instructions in 8086 microprocessor
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