PDA

View Full Version : ISA->LPC bridge?



geoffm3
February 18th, 2014, 05:57 PM
Just curious if something like this exists... it seems like it might potentially be a good homebrew project for old PCs... an ISA to LPC (low pin count) interface/bridge. Most PCs include a multifunction LPC controller on them to handle sound, fdc, and other low speed I/O. Seems like it might be a good way to get a cheap modern replacement for ISA cards.

NeXT
February 18th, 2014, 06:14 PM
I would suspect that such a device would cost a small fortune. You're basically describing a modern multifunction card beyond the traditional Ram/RTC/Parallel/Serial card.

geoffm3
February 18th, 2014, 06:20 PM
I would suspect that such a device would cost a small fortune. You're basically describing a modern multifunction card beyond the traditional Ram/RTC/Parallel/Serial card.

Looks like one example, LPC47U33X is available from the chinese suppliers on eBay at onsey twosey prices of $11.50-25.00. Of course there's all the IO for the peripherals and a CPLD or FPGA though. Looks like there's a reference LPC host core on Altera's website.

cr1901
February 18th, 2014, 08:52 PM
LPC to ISA bridges exist- modern motherboards with ISA slots wouldn't be possible without them. From what I've been told by someone who in fact owns such a modern board with real ISA slots, the two current manufacturers of such chips are Winbond and Fintek. Sorry, I don't have any part numbers.

Chuck(G)
February 18th, 2014, 09:18 PM
Well, Opencores (http://opencores.org/project,wb_lpc) offers an LPC host design, but it probably would take some tweaking. Lattice had some reference designs for LPC host as well. But consider that LPC is what, over 15 years old? That puts it back in the "old" if not "vintage" days. Would creating an LPC to ISA interface be worth the time investment?

Reading the datasheet, the LPC47U33X is an LPC peripheral, not a host. I suppose a ISA to LPC host could be constructed, but it'd be a pretty big job--and probably not worth the effort.

geoffm3
February 18th, 2014, 09:26 PM
Reading the datasheet, the LPC47U33X is an LPC peripheral, not a host. I suppose a ISA to LPC host could be constructed, but it'd be a pretty big job--and probably not worth the effort.

Yes, that's right... the referenced part is mostly a super IO with some extra functions.

geoffm3
February 18th, 2014, 09:34 PM
LPC to ISA bridges exist- modern motherboards with ISA slots wouldn't be possible without them. From what I've been told by someone who in fact owns such a modern board with real ISA slots, the two current manufacturers of such chips are Winbond and Fintek. Sorry, I don't have any part numbers.

Yeah, LPC->ISA is the usual way they're used since they supply more modern PCs with the lower speed interfaces of even older machines... I was referring to going the other way around... attaching LPC peripheral chips to an interface to allow an ISA based machine to use them.

eeguru
February 18th, 2014, 09:40 PM
There are ISA super I/O chips available from Chinese brokers. I have a whole tray of SMSC FDC37B787's (qty 50) if someone is interested in making a project. eg. There are easier ways to get Super I/O than coming from LPC.

I also use a Winbond W83626G LPC-ISA bridge on my mini-motherboard design.

Chuck(G)
February 18th, 2014, 10:17 PM
One could also use a PCI->ISA bridge IC (NS has one, PC87200 --and so does Winbond, the W83628 and 629), or even the ARS USB-to-ISA converter