Coupon Accepted Successfully!


Interfacing Of 8259A With 8085


Interfacing Of 8259 With 8085 Microprocessor


The interfacing steps are explained below:

  • The address decoder output is connected with the CS input of the IC.
  • A0 line is used to select one of the two internal addresses in the device. This is connected to A0 of the address lines of the microprocessor.
  • As the device operates in I/O mapped I/O mode, the RD and WR signals are connected to IOR and IOW signals respectively.
  • The interrupt INT pin of 8259 is connected to the INTR input of the 8085 microprocessor.
  • INTA output of the processor is connected to the INTA input.
  • When SP / EN pin is high, only one IC is used in the microprocessor-based system. If more than one IC are connected in cascade, this pin must be low.
  • CAS0, CAS1 and CAS2 lines are generally opened.
  • There are eight IR input lines (IR0–IR7) are available. When the IR inputs are not used, they must be grounded properly to avoid noise pulse in interrupt lines.

Test Your Skills Now!
Take a Quiz now
Reviewer Name