Page 160 - Digital Electronics by harish

Hardware interrupts : These interrupts are given by the peripheral devices to
the interrupt pin (hardware) of the microprocessor. Hardware interrupts are also
called external interrupts.

Software interrupts : These interrupts are internally generated within the
microprocessor using software instructions. Software interrupts are also called
internal interrupts.

Maskable interrupts : These external interrupts can be delayed or rejected by
the microprocessor.

Non-maskable interrupts : These external interrupts cannot be delayed or
rejected by the microprocessor. Non-maskable interrupts are used for handling
emergency situations.

Vectored interrupts : When the address of the Interrupt Service Routine (ISR)
is fixed within the microprocessor itself, then the interrupt is called Vectored
interrupt.

Non-vectored interrupts : When the address of the Interrupt Service Routine
(ISR) is supplied by the peripheral device, then the interrupt is called Non-
vectored interrupt.

5.4.2.2 8085 interrupts

In 8085 microprocessor, there are 5 interrupts as shown in figure 5.16.
1. TRAP
2. RST 5.5
3. RST 6.5
4. RST 7.5
5. INTR

Figure 5.16 : 8085 Interrupts
In additional to these hardware interrupts, 8085 microprocessor has eight
software interrupts. The RESTART instructions RST 0 to RST 7 are software
interrupt instructions.

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