The Sinclair QL Forum

Just to double check.

This is what I see when looking inside the QL slot.

From left to righ
"B" row top, GND, D2, D1, D0, ...
"A" row bottom, GND, D3, D4, D5, ...

Correct?

TCAT

Tobias, "A" pins are on the edge, I was afraid so. Meaning that "A" row contains most of the address and data line pins, this makes it difficult for track routing. To reach address and data pins on the PCB the tracks would have to go between many "B" row pins. Correct? ...

Hi All, I have started my PCB design, as it seems a better option to using prototype backplane board. I seem a little bit confused about DIN expansion connector pinnout. QL Concepts Guide gives such pinout as MALE, I guess I need to put FEMALE in the design, but there is yet another view such as sol...

Hi,

Trying to asses the ideal PCB width.
I have only a connector with straight pins, 90 degree angle pins would be better.
I taped it onto the cardboard edge, it inserts inside QL more or less smoothly.

TCAT

Brane, I see your point, finding a suitable place inside QL, on top of CPU where most of the signals are provided already, use IDE ribon cable to make connections. Short and quick uncomplicated path, saving PCB and voltage regulator design. I am afraid of doing internal upgrades for my lack of skill...

Hi All, I take your advise SRAM and GAL makes a good ground for the design. I wish to start with an updated GAL equations based on Brane's guidance, It is commented I hope you can follow. GAL16V8 Glue logic for 512x8 SRAM Sinclair QL RAM Expansion (c)2014 Sinclair QL forum # control bits set by asse...

Hi All,

Do you mind following this link, I feel this went slightly off topic, I wish to make a "leap" from GERT INTERNAL design to DIY board design and recommended components list.

http://qlforum.co.uk/viewtopic.php?f=2&t=877&start=10

Many thanks
TCAT

This is part of the QubIDE schematics. Just connect a 512KByte SRAM chip to the bus and the 16V8 GAL. Anything else? :) Greetz from Brazil Greetings to Brazil, You have very simplistic design I looked at your GAL equations as well. I'm sure it must work like a charm. CHIP AMP512 GAL16V8A A19=1 DSL=...

Dave, Mark,

Thank you so far.
I will use L78M05 with 350mA, and capacitors in the range you advised.

TCAT

For the relatively simple job that the GAL is doing, and it will not be operating with any really high speed cycles, the current consumption should be at the lower end. As such, using a 7805 voltage regulator should be okay. Fit it flat to the board and put a large area of copper track around the t...