What is the interrupt number in 8085 microprocessor and how to find interrupt's vector address?
The 8085 has five interrupts, INTR, RST5.5, RST6.5, RST7.5, and
TRAP. It also has eight software interrupts, RST0, RST1, ...,
RST7.
The INTR interrupt requires a hardware response that is an
opcode. Usually, the opcode is either a CALL instruction, in which
case the interrupt vector can go anywhere in memory, or it is an
RST instruction, in which case the vector is based on a table in
low memory.
In the case of RST instructions, either directly or via INTR, or
the RSTx.5 interrupts, you simply multiply the interrupt number by
8 to get the vector address. The following table presents the
vector addresses for all possible interrupts...
RST 0 - 00H
RST 1 - 08H
RST 2 - 10H
RST 3 - 18H
RST 4 - 20H
TRAP - 24H
RST 5 - 28H
RST5.5 - 2CH
RST 6 - 30H
RST 6.5 - 34H
RST 7 - 38H
RST 7.5 - 3CH