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Interrupt
The document discusses interrupts in computing, defining them as signals from devices or programs that prompt the operating system to respond. It categorizes interrupts into software and hardware types and further classifies hardware interrupts into maskable and non-maskable. Additionally, it covers the functionalities of specific instructions like SIM and RIM, as well as the concept of Direct Memory Access (DMA) and its advantages and disadvantages.
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Interrupt
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- 2. What is Interrupt? An interrupt is a signal from a device attached to a computer or from a program within the computer that requires the operating system to stop and figure out what to do next. 7/22/2018 Joyanta kumar Sarker 2
- 3. Types Of Interrupt 1.SoftwareInterrpt 2.Hardware Interrupt Maskable Interrupt Non-Maskable Interrupt 7/22/2018 Joyanta kumar Sarker 3
- 4. Diagram of Interrupt Interrupt Hardware Maskable Non- Maskable Software 256Types of Software Interrupt 7/22/2018 Joyanta kumar Sarker 4
- 5. Hardware Interrupt Hardware interruptsare generated by hardware devices when something unusual happens; this could be a keypress or a mouse move or any other action. 7/22/2018 Joyanta kumar Sarker 5
- 6. Software Interrupt A softwareinterrupt is a type of interrupt that is caused either by a special instruction in the instruction set or by an exceptional condition in the processor itself. 7/22/2018 Joyanta kumar Sarker 6
- 7. Those interrupts whoserequest can be denied by microprocessor. - -RST 1, RST2, RST 5, RST 6.5 etc.. 7/22/2018 Joyanta kumar Sarker 7
- 8. Non-Maskable Interrupt Interrupts whoserequest cannot be denied. eg -RST 4.5 -TRAP -RESET IN. 7/22/2018 Joyanta kumar Sarker 8
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- 10. Differences between Maskableand Non-Maskable 7/22/2018 Joyanta kumar Sarker 10
- 11. RIM(Read Interrupt Mask) RIM is a multipurpose instruction used to Read the status of interrupts 7.5, 6.5, 5.5 To read serial input data bit. Loads 8-bit data in the accumulator. RIM does the following three tasks: 1. Read the interrupt mask (bit 2, 1, 0). 2. Identify pending interrupts (bit 6, 5, 4). 3. Receive serial input data bit (bit 7). Joyanta kumar Sarker 117/22/2018
- 12. SIM(Set Interrupt Mask) Canmask or unmask RST5.5, RST6.5, andRST7.5 Reset the pending RST7.5 flip flop Set or reset the SOD(Serial Output Data) pin. SIM does the following three tasks: 1. Mask the interrupts (bit 2, 1, 0). 2. Reset RST 7.5 (bit 4). 3. To implement serial I/O (bit 7, 6). Joyanta kumar Sarker 127/22/2018
- 13. TRAP TRAP is anon-maskable interrupt having the highest priority among all interrupts. It consists of both level as well as edge triggering and is used in critical power failure conditions. It is enabled until it gets acknowledged. This interrupt transfers the control to the location 0024H. RST7.5 It is a maskable interrupt, having the second highest priority among all interrupts. When this interrupt is executed, the processor saves the content of the PC register into the stack and branches to 003CH address. Joyanta kumar Sarker 137/22/2018
- 14. RST 6.5 It isa maskable interrupt, having the third highest priority among all interrupts. When this interrupt is executed, the processor saves the content of the PC register into the stack and branches to 0034H address. RST 5.5 It is a maskable interrupt. When this interrupt is executed, the processor saves the content of the PC register into the stack and branches to 002CH address. Joyanta kumar Sarker 147/22/2018
- 15. SIM INSTRUCTION Set InterruptMusk Controls Hardware Interrupts Implicit addressing mode 7/22/2018 Joyanta kumar Sarker 15
- 16. How SIM Interpretsthe Accumulator 7/22/2018 Joyanta kumar Sarker 16
- 17. SIM and theInterrupt Mask To set making bit for interrupt RST 7.5, RST 6.5 , RST 5.5 To reset RST 7.5 flip-flop To implement serial input output 7/22/2018 Joyanta kumar Sarker 17
- 18. DMA Direct memory access(DMA) is a feature of computer systems that allows certain hardware subsystems to access Memory , independent of the (CPU). DMA is also used for intra-chip data transfer in multi-core processors. DMA can also be used for "memory to memory" copying or moving of data within memory. DMA can offload expensive memory operations. 7/22/2018 Joyanta kumar Sarker 18
- 19. Advantages of DMA Computer system performance is improved by direct transfer of data between memory and I/O devices CPU is free to perform operations that do not use system buses Disadvantages of DMA In case of burst mode data transfer, the CPU is rendered inactive for relatively long periods of time. 7/22/2018 Joyanta kumar Sarker 19
- 20. Maskable Interrupt Process Enabled using the EI instruction. checks for every instruction If there is an interrupt, and if the interrupt is enabled using the interrupt mask, the microprocessor will complete the executing instruction, and reset the interrupt flip flop. 7/22/2018 Joyanta kumar Sarker 20
- 21. Masking RST 5.5,RST 6.5 and RST 7.5 These three interrupts are masked at two levels: EI/DI instructions. The Interrupt Enable flip flop controls the whole maskable interrupt process. Through individual mask flip flops that control the availability of the individual interrupts. These flip flops control the interrupts individually. 7/22/2018 Joyanta kumar Sarker 21
- 22. Maskable Interrupts andvector locations 7/22/2018 Joyanta kumar Sarker 22
- 23. EI ( EnableInterrupt ) This is a 1 byte instruction . The instruction sets the interrupt enable flip- flop & enables the interrupt process . System reset or an interrupt disables the interrupt process . 7/22/2018 Joyanta kumar Sarker 23
- 24. DI ( DisableInterrupt ) This is a 1 byte instruction . The instruction resets the interrupt enable flip- flop & disable the interrupt . It should be included in a program segment . 7/22/2018 Joyanta kumar Sarker 24