Question

List the five groups of interrupts supported by 8086/8088 microprocessor. Discuss the importance of the above five groups of interrupts. PLEASE TYPE

Answer 1

The five groups of interrupts supported by 8086/8088 microprocessor are :

a) Hardware Interrupts

The interrupt is caused by any peripheral device by sending a signal through a specified pin to the microprocessor.The primary sources of interrupts, however, are the PCs timer chip, keyboard, serial ports, parallel ports, disk drives and other peripheral devices.

b) Maskable interrupt

Whenever an external signal activates the INTR pin, the microprocessor will be interrupted only if interrupts are enabled using set interrupt Flag instruction.. If the interrupts are disabled using clear interrupt Flag instruction, the microprocessor will not get interrupted even if INTR is activated. That is, INTR can be masked.

c) Non maskable interrupt

The processor provides a single non-maskable interrupt pin (NMI) which has higher priority than the maskable interrupt request pin (INTR). The NMI is edge triggered on a LOW-to-HIGH transition. The activation of this pin causes a type 2 interrupt.

d)Software Interrupt

Some instructions are inserted at the desired position into the program to create interrupts. These interrupt instructions can be used to test the working of various interrupt handlers. It includes - INT(Interrupt instruction with type number), INT 3(Break Point Interrupt Instruction), INTO(Interrupt on overflow instruction).

e) Reset

The 8086 RESET is required to be HIGH for greater than 4 CLK cycles. The 8086 will terminate operations on the high-going edge of RESET and will remain dormant as long as RESET is HIGH.The low-going transition of RESET triggers an internal reset sequence for approximately 10 CLK cycles.