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Ithaca Audio VIO card.

This was Ithaca Audio's (later known a Intersystems) IO card.


The Intersystems Multiple I/O board (VIO) provided the user with a versatile and powerful peripheral interface system for the. S-100 bus.

VIO features included:-
Two independent programmable RS-232 serial ports    
Independently programmable baud rates, 50 to 19200 baud.
Serial ports have current loop capability
Two 8-bit parallel output ports
Two 8-bit parallel input ports TTL levels user definable strobes and acknowledge signals
Eight independent  addressable 1-bit bi-directional open collector control lines
An On-board   programmable 16~priority   level   interrupt   system.
8-bit   or  16-bit  I/O mapped modes or 16-bit memory mapped mode.
On board wait   state generator.
All LSI   fully  buffered.
IEEE  692.2   S-100   standard;   2   or  4 KHz   compatible.

The VIO may be jumpered to occupy any 32 location area on any 32 location boundary in either I/O space or memory space (but not both). The VIO contains two independent serial ports. Each port is equipped with a set of RS-232 drivers and receivers as well as a set of current loop drivers and receivers. Each serial port can be programmed to run asynchronously from 50 to 19200 baud. The signals to and from both serial ports are accessible at the leftmost 50 pin edge connector. Two 25 conductor ribbon cables coming from this connector can each be mass terminated as a standard RS-232 connector to a terminal. The. user may-construct a simple adaptor to configure either of the ports for attachment to an asynchronous modem.
Here is a block diagram for the card:-

VIO Block Diagram

The VIO contains two pairs of TTL level 8 bit parallel ports. Each pair includes an input port with input strobe and data received signal, and an output port with output strobe and peripheral acknowledge signal. The active polarities of the strobes and the acknowledge signals are shunt jumper adjustable. Parallel port pair A is accessible at the middle edge connector. Parallel port pair B is accessible at the rightmost edge connector.
Control Lines Control lines were provided for use as extra status lines for peripherals, lines for handling external interrupts, or for convenient CPU control over external devices,, Each control line is jumper selectable to function as an input line or an output line. The VIO contains 8 independent control lines. Each control line has a separate on-board port address which may be read from or written to. When reading and writing with control lines, only bit 0 of the data byte is significant and represents the inverted state of the control line. Reading a control line port always relays the state of the control line. "Writing to a control line port always sets the open collector control line driver; however, the user has the option whether or not to connect each driver to the corresponding control line. This determines for each control line whether or not the VIO board drives that line or merely receives it. Four of the control lines are accessible on the middle edge connector and the other four are accessible on the rightmost edge connector. Interrupts
There were two versions of the VIO card available; the VIO-1, with interrupt controller, and the VIO~05 without interrupt controller. The interrupt controller version provides the user with a powerful and versatile 16-input prioritized interrupt system which may be configured to interrupt, the CPU at the occurrence of any state change in any area on the VIO board. The interrupt system consists of two eight-input interrupt controllers which may either interrupt the CPU independently or may be cascaded to form one sixteen-input interrupt system. One of the eight-input systems responds to the control lines, with user-adjustable polarity available for each line. The other eight-input system is assigned to the serial and parallel ports, for  interrupt-driven  serial  and  parallel  data  transfer.

The VIO manual can be downloaded here


Other InterSystems S-100 Boards
64K Dynamic RAM   8K RAM   EPROM  IA-Display   FDC   IO-Card    Series-II Z80    Z80-I   ADDA Board   EPROM Burner
FPB  256K Dynamic RAM  16-64K EPROM  HDA  Series_III Z80  6SIO  EPROM Emulator  RTC Board


This page was last modified on 10/25/2013