i need compare between vectored interrupt system and polling
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interrupt vector table
In a computer, a vectored interrupt is an I/O interrupt that tells the part of the computer that handles I/O interrupts at the hardware level that a request for attention from an I/O device has been received and also identifies the device that sent the request. A vectored interrupt is an alternative to a polled interrupt , which requires that the interrupt handler poll or send a signal to each device in turn in order to find out which one sent the interrupt request.
Stopping program flow to execute a special piece of code that handles a event.Non vectored interrupts are generally raised by input/output or slow devices.
Vector interrupt --> when processor directly call the respective isr when interrupt occurs so, address of respective isr is usually save in register. Non interrupt Vector --> In this case when interrupt occurs the processor calls a generic isr and in generic isr uaer has to call respective isr by checking status register.
Yes and no. INTR response requires an opcode fetch sequence from the interrupting hardware device, often a CALL instruction, so there is no vector table in memory for it, because you can CALL any location. On the other hand, some implementations provide an RST instruction as the opcode, making it a vectored interrupt.
polling interrupt is alternative to the vector interrupt , it requires that the interrupt handler poll or send a signal to each device in turn in order to find out which one is sent the interrupt request.....
An interrupt makes the processor to jump to a vectored location in memory where the ISR is written. By observing the vectored locations for various interrupt inputs of 8085, we know that there are only 4 or 8 bytes allocated for ISR. This memory space is not sufficient for writing any code to process an interrupt. So we write a jump instruction that makes the processor jump to a location in user memory and write the ISR starting from that location.Example: suppose there is an interrupt signal to 8085 at RST 6.5. The call location for RST 6.5 is 0034H. The address space available is 4 bytes. So if we write instruction jmp 2300H at 0034H, then we can write ISR in memory locations starting from 2300H.
The Intel 8259A Programmable Interrupt Controller handles up to eight vectored priority interrupts for the CPU. It is cascadable for up to 64 vectored priority interrupts without additional circuitry. It is packaged in a 28-pin DIP, uses NMOS technology and requires a single a 5V supply. Circuitry is static, requiring no clock input.
Since The vectored Location of RST5.5 lie in Half the location of RST5 and RST6 so it is called RST 5.5(RST 5+1/2 ) Explanation: Vector Interrrupt Vectored Location RST 5 0028H RST 5.5 002CH RST 6 0030H Now we add RST5 and RST6 vectored Location's 0028H + 0030H = 0058H Now Devide The Sum by 2 0058H/2 = 002CH Which is Vectored Location of RST 5.5. This You can Check for All other vectored Interrupts TRAP(RST4.5), RST6.5, RST7.5 for 8085 Microprocessor Thanks .............. S C Patidar
When a processor is interrupted to do a particular task,Program counter should be loaded with the the address of subroutine(task).If the processor automatically generates the address then it is known as vectored interrupt.for example if 8085 microprocessor is interrupted through RST 5.5 pin,then processor multiplies 5.5 by 8 and converts it to Hex address.If user has to provide address of subroutine using CALL instruction then it is known as non vectored interrupt