What happens when the INTR signal goes high in the 8085
Explain briefly what happens when the INTR signal goes high in the 8085
The INTR is a maskable interrupt for the 8085. It has the lowest priority and is also non vectored. When this INTR signal goes into the high state the following things occur / take place:
- For every instruction that is executed the 8085 checks the status of this interrupt./
- Till an instruction is completed the signal of INTR will remain high. Once an instruction is completed the processor sends an acknowledgement signal INTA.
- As soon as the INTA signal goes low a new opcode is placed on the data bus for transfer.
- Once the new instruction is received the processor saves the address of new instruction into the STACK and an interrupt service subroutine begins.