ACL-7122
144-Bit Digital I/O Card

Introduction

What is an 8255 PPI?

The 8255 PPI controls 24 bits of digital I/O. It has three 8-bit ports (A, B and C), which can be functionally programmed as either input or output. Ports A and B are always used for digital I/O, while Port C can be configured for digital I/O, control, status or handshaking signals.

Although the 8255 has 3 modes of operation, the ACL-7122 only emulates Mode 0 of the PPI. This mode provides simple input and output for each of the three ports. No handshaking is required as data is directly written to or read from a specified port.

Features

• PC/AT Bus
• IRQ Level: IRQ3, ..., IRQ15
• Compact Sized PCB
• SMT Component Design
• 144 TTL/DTL Compatible Digital I/O Channels
• Emulates Six Industry Standard Mode 0 8255 PPI
• Buffered Circuits for High Driving Capability
• Direct Interface with OPTO-22 Compatible I/O Modules and Racks
• Programmable Interrupt Handling
• Output Status Readback
• Fully Compatible with ACL-722 and Advantech's PCL-722

ACL-7122 is a high-density 144-bit Digital I/O card for the IBM PC/AT computer and compatibles. All 144 digital I/O channels can sink 24mA for power control applications. Six 50-pin ribbon connectors are provided on-board, each one serving 24 digital I/O lines that are pin compatible with Opto-22 I/O racks.

• Digital I/O
  ACL-7122 emulates Mode 0 of an 8255 PPI and its pin assignment is fully compatible with Opto-22 I/O rack and modules. Its digital inputs and outputs are TTL-compatible and use 74LS244 driver/buffer circuits to provide high drive outputs. The circuits also demand less current than regular TTL circuits.

• Interrupt Control
  With the interrupt control circuitry, either PC0 or PC3 from Port C of the ACL-7122's 8255 PPIs can generate an interrupt request. IRQ3 to IRQ15 can be user selected by jumper setting.

• Read-Back
  You can monitor the digital output status by reading directly from the ACL-7122's output ports.

• Power Consumption
  +5V @ 0.9A typical, @ 1.1A max.

• Program Library & Examples
  An extensive library of functions are available that support Microsoft C and Borland C/C++. Example programs are included to demonstrate how to write C programs for the ACL-7122.

• Windows 3.x Driver (ACLS-DLL1)
  The ACLS-DLL1 is a high performance Windows driver for Digital I/O functions. It supplies a DLL that can be accessed from C, C++ and Visual Basic under Windows 3.x environment.

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