The MAB RTU (Remote Terminal Unit) of Infoware Inc. is a modular system
developed primarily for power control applications. My task was to develop the
hardware of an extension card in a communication unit of this system. The main task of
the card is to facilitate communication between multiple external cards and the internal
bus of the unit through various physical interfaces.
My card design is based on a microcontroller unit and a CPLD. The internal
peripherals of the microcontroller handle the external serial comunication on one side,
while the communication on the bus is handled in three main way. Access to a dual-port
RAM is provided within the shared address space on the bus, a high-speed Ethernetconnection
is available for fast communication, and the CPLD handles other special
The aim of this extension card was to handle most physical interfaces in use at
the company using a single board. The physical interfaces can be realised as separate
modules connected by internal connectors to the card. A large variety of interfaces can
be configured using this card.