8085 Interrupts in Microprocessor

8085 Interrupts in Microprocessor:

8085 Interrupts in Microprocessor diagram is shown below

8085 Interrupts in Microprocessor

Polling and Interrupts:

In Polling and Interrupts of the microprocessor’s software simply checks each of the I/O devices every so often. During this check, the microprocessor tests to see if any device needs servicing. Fig. 5.1 shows the flow chart for polling subroutine. This is a simple program which services I/O ports A, B, and C. The polling routine checks the status of I/O ports in proper sequence. It first transfers the status of I/O port A into the accumulator. Then the polling routine block checks the contents of accumulator to see if the service request bit is set. If it is, I/O port A service routine is called. After completion of service routine for I/O port A, the polling routine moves on to test port B and the process is repeated. This test and service procedure continues until all the I/O port status registers are tested and all the I/O ports requesting …

Types of 8085 Interrupts:

The 8085 has multilevel interrupt system. It supports two Types of 8085 Interrupts: Hardware     Software Hardware : Some pins on the 8085 allow, peripheral device to interrupt the main program for I/O operations. When an interrupt occurs, the 8085 completes the instruction it is currently executing and transfers the program control to a subroutine’ that services the peripheral device. Upon completion of the service routine, the CPU returns to the main program. These types of Types of 8085 Interrupts, where CPU pins are used to receive interrupt requests, are called hardware interrupts. Software : In software interrupts, the cause of the interrupt is an execution of the instruction. These are special instructions supported by the microprocessor. After execution of these instructions microprocessor completes the execution of the instruction it is currently executing and transfers the program control to the subroutine program. Upon completion of the execution of the subroutine program, …

Updated: January 24, 2020 — 12:10 am