68000 CPU system on mid-90's military board - Page 1
Forum section: electronics / general

author: D Straney
author_rank: Frequent Contributor
timestamp: February 08, 2024, 04:33:06 am
content: Thought some people might be interested in seeing an appropriately "vintage-computing" CPU showing up in a (relatively) modern special application. I got this board as one of a set being sold as interesting-looking gold scrap, with no info on the source (I didn't see any other boards from the same seller that could be from the same system). Date codes are from the mid-90's.Where does this come from?Interstate Electronics of Anaheim, CA as labeled on the bottom (now a part of "L3Harris"), as far as I can tell, seemed to make GPS receivers and related equipment for the military: their former website "iechome.com" now redirects here:https://www.l3harris.com/all-capabilities/m-code-navigation-solutionsThe CAGE code 12339 from the label on the top corresponds to "DRS TRAINING & CONTROL SYSTEMS", which seems now to be part of Leonardo, a big European defense conglomerate. My best guess, based on these two companies being involved, is that this is part of a navigation system from a pilot-training air combat simulator. As opposed to entirely-ground-based flight simulators, these often involve an extra pod full of hardware attached to a real plane, to relay telemetry in both directions, and allow playing out training scenarios with a real plane in the air, controlled from the ground. You can see some examples of this here:https://www.leonardodrs.com/what-we-do/products-and-services/acmi-pods-subsystems/(I always feel a little like I need a shower after reading through a lot of "defense" industry website copy, but it's helpful in identifying where interesting electronics scrap like this came from)What's on the board?You can see more photos here:https://www.flickr.com/photos/147639706@N02/albums/72177720314646603/This looks like a pretty standard processor board as far as electronics goes, with some slight twists.Processing:∙ Hitachi "HD68***00Y10" (with the 3 digits covered by the strap) is almost definitely an HD68HC000 processor, a CMOS CPU using (obviously) the 68000 architecture∙ Hitachi HD63450 is a DMA controller∙ LSI L1A4162, the big ceramic gold-cap guy at the edge, is likely some kind of ASIC which I can't find any references to; might be some kind of coprocessorYou can tell from the gap in the conformal coating that it used to have a strap holding it into its socket, just like the HD68HC000.∙ Windowed CLCC package is a 27C1024 EPROM - probably program code∙ (2x) Omni-Wave OW62256 (labels gone here, read from a different copy of the same board) is a 32k x 8 SRAM - probably program memory for the 68000∙ 5962-8752702YA / Zilog Z0853004LMB is a serial interface (USART)∙ 5962-8688802CA = NSN 5962-01-281-8198, quad diff. line receiver (equivalent to MC1489AL, SNJ55189AJ)∙ 5962-8688901CA = NSN 5962-01-281-7521, quad line driver (equivalent to LM1488D, SNJ55188J)These line drivers & receivers probably are the physical-layer transceivers for the Zilog serial interface chip mentioned above.∙ IDT 7201LA120LB is a 512 x 9 FIFO memory∙ "Q-Tech" metal cans are likely oscillatorsInterface:∙ (7x) QCPL-1875 is a mystery, but going by similarly-numbered parts (HCPL-* series) I'm guessing it's a quad optocoupler, and these provide isolated discrete digital inputs or outputs to/from external equipment (such as the other avionics in the aircraft which it would need to interface with)∙ (5x) 54FCT244DMQB is a standard 74x244 octal buffer with a 3-state output - useful for muxing multiple sets of digital inputs onto the CPU's data bus, such as the inputs from the QCPL-1875s mentioned above∙ Windowed DIP package 5962-88724 is a UV-erasable PLA - best guess is that this does CPU address bus decoding & interfacing for the peripherals on this board, selecting the EPROM/RAM chips and the '244 buffers as appropriateSo overall, it's a 68000 processor board with some DMA, a serial interface, and discrete digital I/O to the the outside world. The FIFO and the LSI ASIC are the big mysteries here. With the number of pins on the LSI ASIC, it sure seems like it does something complicated - if this is part of a GPS system I could see that being used for specialized navigation calculations or timing to offload that work from the general-purpose processor (plenty of trigonometry needed to find your position). I can't follow the visible traces, but by the placement of the FIFO and the '244 adjacent to it, these two parts look like they might have something to do with the LSI ASIC.Let me know if you have any more info.

author: David Hess
author_rank: Super Contributor
timestamp: February 08, 2024, 04:50:55 am
content: I am always amazed how dense boards get when there is a budget for as many layers as needed.All of the ICs are ceramic packages so I assume it was a military or aerospace application, but that is hardly news given who made it.

author: berke
author_rank: Frequent Contributor
timestamp: February 08, 2024, 05:27:41 pm
content: Maybe it's a Eurocard with a DIN41612 connector that is supposed to go into a VMEBus backplane.