State the different hardware interrupts with their priorities and branching addresses.
What are the Hardware Interrupts ? Explain Vectored and Nonvectored Interrupts of 8085 MPU.
What are Hardware Interrupts? List them according to priority. Also state call location of these interrupts.
Solution
8085 provides 5 hardware interrupts:
(i) TRAP (ii) RST 7.5 (ii) RST 6.5 (iv) RST 5.5 (v) INTR
(1) These interrupts are vectored interrupts. It means that when these interrupts are given , it is directed (or vectored) to transfer the control to specific memory location given by
TRAP = 4.5×8 = 0024H RST7.5= 7.5 x 8 = 003C H
RST 6.5=6.5x8 = 0034 H RST 5.5 = 5.5 x 8 = 002C H
(2) Among these interrupts, TRAP is non- maskable interrupt which can not be disabled. But the other four interrupts are maskable interrupts, which can be disabled.
(3) The TRAP has highest priority and the INTR has lowest priority among the hardware interrupts. The hardware interrupts in descending order of priority are listed below:
(i) TRAP - highest priority (ii) RST 7.5 (iii) RST 6.5 (iv) RST 5.5 (v) INTR - lowest priority.
