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RE: [N8VEM-S100:1169] Re: S-100 PCB reorder status

Hi Dave!  Thanks!  I am very interested in this!


In addition the SDRAM logic may also have application to the S-100 80386 CPU board since it has the same conundrum as the MC68040 SBC regarding large DRAM.


Thanks and have a nice day!

Andrew Lynch


From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of yoda
Sent: Friday, November 23, 2012 7:44 PM
To: n8vem...@googlegroups.com
Subject: Re: [N8VEM-S100:1169] Re: S-100 PCB reorder status


Hi Andrew


Thanks for the update.  My own personal preference is the 68K CPU and I believe you essentially have 20 waiting on it so I hope it makes it out soon.  Regarding the LAVA board - I think there might be a better way to do this but have not had time to look deeply into it.  I got a XULA-2 board from xess.com and it looks like it will do a lot more than the LAVA can and I want to explore the SDRAM that it has on it - may be a better way for us to get to large memory than the 68360 we have been looking at (I have not given up on it yet - still plugging away on it - I think the problem may be in the VCO circuit - I have some debug ideas I am working on)


On another note - what would it take to get some S100 unbuffered proto boards made - I have a couple of buffered boards but I want to try a different approach and could use the extra real estate that the unbuffered board has.  I am willing to help fund the reorder of this board (would pay for a significant number of them).  Was wondering if any one else is interested in that board - think I saw 6 on the list.





On Friday, November 23, 2012 6:07:53 PM UTC-6, lynchaj wrote:

Hi Dave!  Thanks!  The story on the S-100 68K CPU board is that I got frustrated with its poor layout and trace route optimization.  It was stalled out at 375+ vias and held there for literally months and never seemed to make much progress in the optimizer.  I think the problem was the chips were oriented up and down versus side to side like all of the other S100computers.com and N8VEM S-100 PCBs.  It was just an “odd duck” and never seemed to fit in or do well.


Considering its lack of progress, I did an experimental V3 board where I reoriented all the chips and reworked the PCB layout completely.  Wow! What a difference it made!  After only about 3 to 4 weeks of optimization the S-100 68K CPU board is now at 204 vias and dramatically less overall trace length.  Since there were no changes to the schematic or resulting circuitry I think the board should operate as well if not better than the prototypes.


I am thinking that the new S-100 68K CPU board should actually be done much sooner than otherwise would have considering the rate of progress has improved so much.  There is no way to recover the lost months but at least we are now on a path to a solid board without overly complex trace routing.


The S-100 LAVA board is completely ready to go and has been sitting in the ready queue for months awaiting the S-100 board reorders, etc to clear out.  What’s next depends on which board completes first either the S-100 68K CPU board or the S-100 80286 CPU board.  I am guessing the S-100 68K CPU board since it is at 204 vias versus the S-100 80286 CPU board at 292 vias.


I hope this helps!  Have a happy holidays!

Andrew Lynch


From: n8ve...@googlegroups.com [mailto:n8ve...@googlegroups.com] On Behalf Of yoda
Sent: Friday, November 23, 2012 12:12 PM
To: n8ve...@googlegroups.com
Subject: [N8VEM-S100:1167] Re: S-100 PCB reorder status


Hi Andrew!!


What about the 68K board ? I thought it has been in the queue for a long time.  If it is still being held up by routing, I was thinking why not replace the 68K chip with the 68000fn12 which is a plcc 68 and the 2 roms with a at29c1024 which is a plcc 44 and a single chip vs 2 - this would free up a lot of space on the board and be the same exact functionality as now.  It should make routing the board easier and cut down the chip density.  The 68K is 5 dollars I believe from utsource and I think the 29c1024 is approximately the same from utsource.  Just a thought.





On Friday, November 23, 2012 9:56:58 AM UTC-6, lynchaj wrote:


Some good news!  We’ve eliminated the backlog of S-100 PCBs and made some progress on the other N8VEM PCBs as well!


I would like to start reordering PCBs again soon now that some funds have freed up.


In particular I’d like to start with the S-100 LAVA PCBs  since they are ready for manufacture and been sitting in the queue the longest. 




There are 11 builders in the queue for the S-100 LAVA board but most likely the list is out-of-date and needs an update.


A viable PCB manufacturing order is at least 20 orders just to pay for the boards, tooling, shipping, etc.


Please review the list and send me any updates -- especially if you *do not* want to get a PCB on the list!


I understand the economy is difficult everywhere and plans change however the builder PCB drop-out rate is impacting my ability to get boards.


Here is the current inventory of PCBs (link and attachment).  As you can see there are many boards still available for the ECB systems as the S-100 boards have all gone to their builders.  I sincerely appreciate your assistance in helping clear this up!




Thanks and have a happy holidays!

Andrew Lynch


PS, if cash and/or paypal is an issue, we can make trades for certain computer parts, electronic components, tools, metals, coins, unused gift cards, shipping materials, scrap, etc.  Please let’s discuss!