The humongous Sandy Electronics thread...

[Dave]

I'm lucky to only be designing boards with no internal cuts or angles.

QL2 might have some interesting panels though - it is likely to have SD storage. That's a whole other discussion...

[Dave]

I am so cross right now.

I received the SMD 47uF caps for SuperRAM, checked them then put them on the SuperRAM shelf. Now, I can't find them.

SHUT. DOWN. EVERYTHING!

[Dave]

My cunning ploy worked!

I posted here, and five seconds later I found them

[tofro]

That's easy - Just decide you don't need them anymore and search for something else and the stuff normally shows up immediately

Tobias

[Dave]

One of the design considerations of this board is that it has to work as an upper deck daughter card to UltimIDE. For this reason, I changed the power capacitors from radial to SMD - they have a lower profile and are far less likely to be damaged.

I am hoping to have the prototype running this weekend. It would be really great to post some photos and video of it running in my test bench QL.

[Dave]

A late night spent checking parts of the PCB layout of SuperRAM.

I etched a PCB And fitted the power supply section. It works well. Power's getting to all the places it needs to go. All the points are grounded that need to be.

The next step will be to recheck my layout around the GAL, so the pinout is known to create the custom logic.

[Dave]

After a good play with this board, I have decided to change things around a little.

Previously, I had the power regulator at the top of the board (the only sensible place), the RAM dead center and the logic at the bottom. The problem here is that the Address and Data lines are concentrated in the lower area of the board. This causes two problems: the logic and associated diodes and passives are very crowded, and there are some long lines going to the top left of the board - the SP0-3 lines on the thru-connector. I used a signal generator to put some 7.5MHz, 3.75MHz and 1.875MHz TTL square waves into various lines (clock, clock/2 and clock/4) and found a couple of problem areas.

My solution is to move the memory below the logic.

I have a couple of busy days ahead, so it will be 3-4 days until I have the revised design completed. I'm helping a neighbor with some painting to supplement funds a little bit. Some people don't realize that Sandy is now my "day job"...

[Dave]

I just invested in a new oscilloscope. It's a huge ding, but I'll live. My previous second hand purchase was not what it claimed and was relabeled to be a much better model than it actually was.

I got a Rigol DS1072U 70MHz digital 2 channel oscilloscope for $345 shipped. I'll get a 16 channel logic analyzer later. If I am going to be doing work of the very highest standards, I will need at least good quality tools, even if they are not high end.

[prime]

I got a Rigol DS1072U 70MHz digital 2 channel oscilloscope for $345 shipped. I'll get a 16 channel logic analyzer later. If I am going to be doing work of the very highest standards, I will need at least good quality tools, even if they are not high end.

I Have the Rigol DS1052e, and have found it invaluable, better than the analog 20MHz scope it replaced.

Cheers,

Phill.

[Dave]

I have had three of my battery holder shipments to the EU returned to me by USPS. They apparently read "battery holder" on the customs form, and declined to put them on the plane but just shipped them back to me, because USPS does not like to ship batteries. I do know that one has been delivered to Germany.

I am going to re-ship the returned parts tomorrow morning, but declare the contents as an "adapter" and see if we do better.

I am also sending a number of these to Rich at RWAP, so he will be able to ship them within the EU quite easily.

I do apologize to people who are affected by this - it's a learning process.