Instruction Manual

ISO-16 User Manual

Interrupt Control

When enabled, interrupts are generated on Port A bit D0.

IRQEN

Interrupt enable 1 = enabled 0 = disabled ( 0 on power up )

IRC0

IRC1

Interrupt mode select, see table below

Interrupt Mode Select Table

Interrupt source is Base+0 bit D0. When selecting the Interrupt Type, always disable

interrupts prior to changing or setting states. This will help prevent inadvertent or

unexpected interrupts from occurring.

IRC1 IRC0 Interrupt Type

0 0 Low Level

0 1 High Level

1 0 Falling Edge

1 1 Rising Edge

Warning: When using the High and Low Level interrupts, an interrupt occurs when

input D0 changes to either a High or Low state. This will cause the computer to

remain in an interrupt state until the input state changes.

Interrupt Read

Reading the Interrupt Status port (Base+5) clears any interrupt pending.

IRQST (D0) Interrupt Status 1 = interrupt pending, 0 = none