The GDU 020 is an intelligent peripheral device packaged on a single standard EURO Size pcb, forming part of the extensive ABACO® family of professional boards. A complete, high resolution video-graphic terminal, the GDU 020 is capable of operating both interfaced with the ABACO® Industrial BUS and in stand-alone mode.
The GDU 020 is controlled by the Master CPU in the same way as any other peripheral device of the family. Notable on-board resources and the availability of local intelligence ensure that the GDU 020 is able to pilot all display operations standing alone, with no external assistance required whatever. With high speed parallel dialogue and generous input buffer space, commands can be acquired from the CPU by the GDU 020 at over 200,000 bytes per second and processed at the rate allowed by the video section.
This means that the CPU remains free to operate at full speed and without any call on its resources to provide video management as occurs typically in non-intelligent units. Operating in stand-alone mode, the GDU 020 becomes an independent and sophisticated video-graphic terminal, complete with keyboard.
The same module can also be connected in serial to operate as a slave, even at a considerable distance from the master CPU, so that use can be made of any given intelligent device provided with a serial communication line, such as a standard PC, or a PLC, etc.
The GDU 020 has interfaces for driving a CRT with composite video or separate synchronizing signals, and will also drive PLANAR Fluorescent Graphic Displays directly. Text is handled by the GDU 020 using a programmable character generator; the single character is treated as a graphic entity of definable dimensions.
The on-board CPU will control the scanning for a passive keyboard of 8x8 matrix, and pilot the operation of up to 8 indicator LEDs. Input from a normal PC Keyboard can also be accepted. With an on-board serial line suitable for RS 232, RS 422, RS 485 or Current Loop, every likely user requirement will be covered. The additional option exists of a piggy-back expansion facility to allow the use of colour in RGB. All settings relative to operating mode, baud rate, type of display etc., are stored in an on-board serial EEPROM.