What is the importance of INTA in 8085 microprocessor?

Answer 1

The INTA- pin on the 8085 is a read strobe that is used in response to the INTR sequence. It has the same timing as RD-, and external hardware is expected to provide an instruction opcode and, if necessary, the extra bytes, in response to INTA-.

One of the enhancements made in the 8085 over the 8085 is the RST type instructions, which are single byte calls to specific locations in low memory. External hardware can be simplified by providing the RST opcode, without needing to provide a full CALL instruction.

Not asked, but answered for completeness - the other four interrupt pins, RST5.5, RST6.5, RST7.5, and TRAP are 8085 enhancements that allow the use of automatic interrupt vectoring without using the INTA- pin.

Answer 2

The INTA- signal is interrupt acknowledge. It has the same timing as RD-. External logic is expected to provide an opcode in response to INTA-.