• 96 TTL/DTL Digital I/O lines, using industry standard 8255 PPI
  
• Plugs into IBM PC/XT/AT Bus or compatibles.
  
• Unidirectional, bi-directional strobed I/O.
  
• Direct interface to wide range of peripherals.
  
• Programmable in High-Level languages like BASIC, TURBO PASCAL, C etc. Programmable even in Machine language.
  
• All 8255s are connected through buffers to PC BUS.
  
• Jumper selectable I/O address.
  
• All contact fingers gold plated.
  
• Dry film laminated to international standards.
  
• Legend printed for easy identification of signal lines.
  
• All I/O pins terminated on standard 50 pin Flat ribbon Cable connector.
  
• Can be used: To monitor contact closure, digital I/O control, connect A/Ds nd D/As or any digital I/O communication.
  
• A GOOD EXPERIMENTAL TOOL for project designs.

96 line TTL I/O card is an add-on card to an IBM computer. It requires one slot of the motherboard. It provides 96 TTL/DTL compatible digital I/O lines using four numbers of industries standard 8255s. Each 8255 IC consists of three ports, an 8bit PA,

PB and PC port. The PC port may also be used as two half ports of four bits, PC upper (PC4-7) and PC lower (PC0-3). Each of the ports and half ports may be configured as input or an output by software control according to the contents of a write only control register in the PPI. The PA, PB, & PC ports may be read as well as written into.

In addition, certain other configurations are possible for unidirectional and bi-directional strobed I/O, where the PC ports are used for control of data transfer.

In this digital I/O card, 16 I/O mapped I/O address locations are used, which are fully decoded within the I/O address space of the IBM PC. The base address is set by a position jumper connection. This allows the user to configure the I/O address without conflicting with other I/Os used or designed within the instrument. Programming is simple whether from assembly language, BASIC, C, C++, PASCAL, assembly, VISUAL BASIC, VISUAL C++ or any other higher level languages. The digital I/O card should first be configured in the initialization section of your program by writing the control register. On power up or reset, all ports are configured as inputs. A variety of configurations are possible by writing the appropriate control code. The 8255 can be programmed in three different modes. Mode 0 - Basic I/O, all ports is I/O ports. Mode 1- Strobed I/O, part of the PC port controls data transfer. Mode 2 - Strobed bi-directional bus.
A sample program in BASIC It is assumed that a switch /LED module, Model IM-6 is connected to this digital I/O card. Where PB is connected to 8 bit Switch inputs and PC is connected to an array of 8 buffered LEDs.

Typical Program in BASIC:

10 PA= &H830C : REM "PA-PORT NUMBER OF 8255-VI
20 PB= &H830D : REM "PB-PORT NUMBER OF 8255-VI
30 PC = &H830E : REM"PC-PORT NUMBER OF 8255-VI
40 MODECON = &H830F : REM: "MODE CONTROL OF 8255-VI
50 OUT MODECON, 130 : REM " SETS PA & PC IN O/P PORT AND PB PORT AS I/P OF 8255-VI
60 DAT = INP (PB) : REM "INPUTS FROM PB PORT,
70 OUT PC, DAT : REM "OUTPUTS CONTENTS OF PB ON PC PORT
80 OUT PA, DAT : REM"OUTPUTS CONTENTS OF PB ON PA PORT
90 LOCATE 12, 30 : PRINT DAT
100 GOTO 60 : REM " REPEAT THE SAME LOOP INDEFINITELY

Specifications:

Four numbers of 8255s are used. All the I/O lines are terminated on a 50 pin FRC on the rear side of the computer.

• 50 pin FRC cable supplied.
  
• Occupies one slot on the motherboard.
  
• Logic inputs and outputs Min Max
  
• Input logic low voltage -0.5V 0.8V
  
• Input logic high voltage 2.0V 5.0V
  
• Input load current PA, PB, PC
  
• (0 Vin 5V) -10uA 10uA
  
• Power consumption 280mA @ +5V
  
• Dimensions 20.5cm x 10cm
  
• All input and outputs are TTL/DTL compatible and each output bit drive TTL load (74 series) or four LS TTL (74LS) loads.

NOTE: You must provide an IBM Computer or Compatible system. It must have at least one vacant ISA slot on the motherboard, to enable the ADD-ON card to be inserted, which will communicate with the trainer. The minimum configuration of the system must be any Intel make standard CPU, 32MB RAM, one 1.44�FDD, HDD with any capacity, CD ROM drive, and a color monitor.