Todd,
I think you will end up with a BGA FPGA which is going to be unfriendly to most builders. You might be able to do something of a hybrid with address and data being external but it will be kind of hard to do as you need to multiplex the address lines. If you think about a 32 bit data and 32 bit address lines with clock and other signals you pretty much have eliminated any QFP type package for a FPGA. I have been looking at the Saturn Board from Numato.com which makes a small board with a hefty Spartan 6 on it and 32MB of SDRAM - wish it had more but there are probably enough I/O pins to add more I think. I am looking at this as a multipurpose mezzanine board for the ECB and S100 busses - provide PIC, RTC, SD card, and hi res SVGA or greater with graphics. Probably half of the memory could be used by system and the other half by graphics is what I am hoping. Then in one board could provide memory and almost any type of I/O that you want by simply "re-programming" the FPGA.
Dave
On Wednesday, July 30, 2014 7:01:43 AM UTC-5, Todd Goodman wrote:
Perhaps, the DRAM board is a good one to start with an FPGA to handle
the whole DRAM controller so that current memory can be used?
Todd
* John Monahan <mon...@vitasoft.org> [140729 19:26]:
> I have so far absolutely no experience with Linus Andrew. My very long term goal is to have it on all of the boards mentioned below, should be doable. The “Achilles heel” of the 80386 system right now is RAM. I think we can get to 64MG with the daughter board but that system really requires a SIMM in the GB range. That will require a difficult board to layout involving a DRAM refresh circuit. This is currently past my capability and I have toyed with the idea of offering financial “a reward” to the first person that provides me with a practical design that I can get to work. Probably later in the year anyway as the is a backlog right now.
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> John
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> From: n8ve...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Andrew Bingham
> Sent: Tuesday, July 29, 2014 1:34 PM
> To: n8ve...@googlegroups.com
> Subject: [N8VEM-S100:4731] Re: An ARM CPU on the S100 bus
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> John,
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> I was trying to find information the other day on historical ARM CPUs thinking about this as well.
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> One thought though - would writing Linux drivers to use the GPIO pins on this module to interface with the S-100 IO boards be more or less difficult than writing Linux drivers to be able to use the 386 board, or re-spinning the 68000 board to support one of the later 68k versions that will run Linux? In my mine it seems like we have at least a couple more "direct" options for Linux before going to the highly integrated module.
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> I'd like to see a HD6120 board. But I have more things I'd "like to see" than time to make them happen.
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> Andrew
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> On Tuesday, July 29, 2014 10:58:58 AM UTC-7, monahanz wrote:
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> I have been doing some long term planning as to the direction I would take in doing new S100 boards. To recap, we now have a 6502, Z80, 8080 (Josh), 68000, 8088, 8086, 80286 and soon an 80386 set of boards on the S1000 bus. Andrew and I have already started laying out an 80486 board.
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> Since I do a lot of flying on business I have time to read up on chips and recently I have been thinking what would be the best way to get ARM CPU's on the bus. There are many types, and while one could start with a bare chip it does seem to make more sense to start with an embedded module. There are many of these, most of which boot up Linux immediately. One particular one I'm fairly impressed with is an Italian one called "Aria G25" see:-
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> <http://www.acmesystems.it/aria> http://www.acmesystems.it/aria
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> Also it lends itself to easy pin splicing/layout on a board. It has good documentation and software support. I particularly like the fact that it has 60 GPIO pins. These could be easily spliced into our S100 bus so we could use our current boards for I/O. (In fact at 400MHz, one could also use the S100 RAM!). I know some of you will view this as sticking a Lamborghini engine in a Volkswagen, but would it not be neat to see Linus running on the S100 bus.
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> Comments please, in particular I would be interested in any other similar modules.
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> John
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