2004

LEM - Instruments-Side GPIB Interface Cards for Standalone Instrument

GPIB interface cards were designed for a new generation of power analyzers from LEM Instruments. Cards have the form of a plug-in card with internal bus connector on one side and the GPIB connector on the other side. The internal bus of the instrument is a 33 MHz, 32-bit bus. The main processor of the instrument is the Motorola Cold Fire. The card is designed as a 2 sided PCB. GPIB transfers are realized with a GPIB TNT488 ASIC from National Instruments. The glue logic between the instrument’s internal bus and the GPIB chip is realized with CPLDs. Cards are delivered in small sets according to the customer's request. The software driver for the GPIB interface cards was developed for the operating system MQX of the instrument. The driver supports communication with the GPIB TNT488 chip using PIO, IRQ i DMA in both directions. The driver is a part of the instrument firmware. Maximum transfer rate of this GPIB interface is 1 MB/sec. The card was developed in 2002, since then over 100 cards have been manufactured and delivered.

Realization: Virtual Instrumentation division