8 levels of interrupts.

  • Can be cascaded in master-slave configuration to handle 64 levels of interrupts.
  • Internal priority resolver.
  • Fixed priority mode and rotating priority mode.
  • Individually maskable interrupts.
  • Modes and masks can be changed dynamically.
  • Accepts IRQ, determines priority, checks whether incoming priority > current level being serviced, issues interrupt signal.
  • In 8085 mode, provides 3 byte CALL instruction. In 8086 mode, provides 8 bit vector number.
  • Polled and vectored mode.
  • Starting address of ISR or vector number is programmable.
  • No clock required

Pin diagram