General purpose PDP-11 interface processor

Technical Report · Fri Oct 01 00:00:00 EDT 1982

OSTI ID:6292301

Purtilo, J

The Z80 interface card, which for simplicity we refer to as the Zcard, is a general purpose microprocessor which is directly interfaced to the Whaley multiplexor, itself implemented on PDP-11 series computers at the University of Illinois. The Zcard provides two serial ports at EAI interface levels and contains up to 16K of local memory. The principle function of the Zcard is to serve as an interface in which the user might alter protocols, change interface characteristics (e.g. baud rate, hardware echo, or flow control), or switch between synchronous and asynchronous modes all under software control. In addition, the Zcard provides extra lines for control of external devices (e.g. modem) and input of status data. In the simpliest use, the Zcard runs a program, downloaded from the PDP-11, which emulates the level EIAFB card (previously developed for the Whaley Multiplexor) for serial communication with terminals. Using no flow control, Zcard performance seems superior to that of the EIAFB card in that no characters are lost under normal use (due to the much larger buffer which the Zcard can provide). The Zcard can further distinguish itself from the EIAFB card in that flow control can be enabled by software. A more sophisticated application of the Zcard might include linking several Zcards (using a synchronous option and both of the provided ports) into a network. In this capacity, a ring topology suggests itself as the most immediate choice, although many alternate connection schemes can be envisioned. This report is intended to summarize the project as well as provide an outline for those intending to modify or program the Zcard.

• Research Organization: Illinois Univ., Urbana (USA). Dept. of Computer Science
• DOE Contract Number: AC02-76ER02383
• OSTI ID: 6292301
• Report Number(s): DOE/ER/02383-0087; COO-2383-0087; ON: DE83009574
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
PDP COMPUTERS
EQUIPMENT INTERFACES
DATA PROCESSING
DATA TRANSMISSION
INTEGRATED CIRCUITS
MICROPROCESSORS
MULTIPLEXERS
COMMUNICATIONS
COMPUTERS
DEC COMPUTERS
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUIPMENT
MICROELECTRONIC CIRCUITS
PROCESSING
990200* - Mathematics & Computers