After looking at datasheets for the 273 latches used and 74act74 flipflop used, the worst case propagation delay is something like 12.3ns.

But my NAND gate ACT00 logic which is triggered by the same CAS signals has a lower propagation delay of between 1-9ns.

So despite a 0ns setup time, it’s possible that I’m violating the SRAM setup times during a write by dropping /CE before the addresses have stabilized into the memory.

I haven’t come up with a solution yet, but it will likely involve adding an additional gate or two to increase the propagation delay.

Lots of progress but little time to talk about it.

Here’s the fully populated card installed.  There were two issues identified so far with the PCB design.  One, the battery holder silkscreen was upside down.  The second fix involved an inverter that needed removed whenever we decided to migrates from a flip-flop(74LS74) design to a SR NAND latch made out of NAND(74LS00) gates.

The memory tests are passing at 100% now!@#

However, there is still a minor issue with how the card responds on bootup, and I’m investigating!

Just in time for Christmas, the PCBs have arrived from China.  I used Seeed Studio (Fusion PCB Service) and they look pretty good.  Here’s the first look at them.

I’m just about to solder one up, so wish me luck!

I'm now back home to Summer in New Zealand, complete with a Northern hemisphere cold (sniff!), following my flying visit to Pianeta Amiga, which was held in a rather chilly Bologna in Northern Italy. Nevertheless the Pianeta Amiga show was a fun affair, even though the attendance was quite small compared to previous years. That didn't stop everyone who did attend from having a good time. I will write more about my Pianeta trip in my next blog but, for now I would like to wish all Amiga enthusiasts, whatever your Amiga colour, hue or flavour a very Merry Christmas.

Let's take a look back at 2013 on the AmigaOne X1000!

I placed the order late last night for the PCB!

The PCB design is obviously finished, fully passes the kicad DRC checks, the problems with the footprints were solved.

I’ve decided to go with Seeed Studio’s Fusion PCB service.  This is based on a recommendation from a knowledgeable friend that has been helping me.

The convenience of AmiUpdate has also allowed a few additions to your AmigaOS system. Camd.library was quietly added a few updates back.

So I received all of the SMT parts today, and attempted to verify that I’ve used the right footprints for the parts.

This was a worthwhile effort because I found a few different problems.

Also, digi-key shipped me some mystery chip instead of my 3v supervisor….. they are fixing…..and I have the batteries and battery holders shipping soon as well.

Things are moving along…….

So all the SMT parts have been ordered for the prototype PCB.  Once they come in, I’ll be testing the placement of the parts on top of a printed layout to see if the chips/parts match the layout — if there was a package screw up, and so on.

This board was never optimized for cost per se, but here’s what the major components cost: