User Manual

PIO-48 User Manual

Wait States

The PIO-48 has the option of inserting one 500 nS wait state for each access. This

may be required on certain machines with bus clocks in excess of 8 MHz. With the

wide variety of machines available, no concrete rules exist concerning wait states. If

the PIO-48 doesn't seem to be responding properly, try inserting a wait state.

To enable wait state insertion, set position 8 of the dip-switch to "ON". To disable

wait states, set position 8 "OFF".

Interrupt Headers J5 and J6

The headers marked J5 and J6 allow the use of interrupts with the parallel ports. J5

selects IRQ2 through IRQ7 for Port 1 (U9 and J1), while J6 selects the IRQ for Port

2 (U16 and J3).

IRQ Header E2

Optional Cable Connector P4

Discrete access to both sides of all relays is provided by attaching the

optional cable (CA-108) to pin header P4 with the colored edge of the ribbon

cable attached to pin one. Removing all the jumpers connecting row P1 to P2

places the A-side of each relay at the on-board DB-37 and the B-side at the

optional cable’s DB-37.