Search found 991 matches

by Chr$
Thu Jun 30, 2022 11:02 pm
Forum: Hardware
Topic: DIY RAM EXPANSION
Replies: 98
Views: 45406

Re: DIY RAM EXPANSION

OK, In the ZIP file attached there is the GAL program with a Enable pin. (a .JED file for direct program the gal and a .PLD program for compile with winculp) To work as a memory upgrade, PIN 2 should be conected to 5V, if it's conected to 0V, the memory expansion will be disable. You can use a SPDT...
by Chr$
Wed Jun 29, 2022 9:45 pm
Forum: General QL Chat
Topic: Vacuum forming dongles
Replies: 5
Views: 197

Re: Vacuum forming dongles

Yes that looks right.

I notice on the 3D model of the plastic upper part, it should be higher, actually about 21mm in height (they are quite chunky). This is probably to allow enough space for the EPROM(S) to be socketed.
by Chr$
Wed Jun 29, 2022 1:21 pm
Forum: General QL Chat
Topic: Vacuum forming dongles
Replies: 5
Views: 197

Re: Vacuum forming dongles

If you want to check your PCB size specs: The original board is 84mm long by 38mm wide. The circular cut-outs are 8mm diameter at the widest part (the edge of the PCB) and are 5mm deep into the PCB, therefore the distance at the narrowest part of the PCB from one cut out to the cut out on the other ...
by Chr$
Wed Jun 29, 2022 12:26 pm
Forum: Hardware
Topic: DIY RAM EXPANSION
Replies: 98
Views: 45406

Re: DIY RAM EXPANSION

Silvester wrote:In addition to spare input pin (for enable switch) it will require RESET (to clock enable/disable condition through only on reset). Something I forgot to mention Chr$ :oops:

A connection to RESET on the CPU you mean? That shouldn't be a problem.
by Chr$
Wed Jun 29, 2022 11:34 am
Forum: Hardware
Topic: DIY RAM EXPANSION
Replies: 98
Views: 45406

Re: DIY RAM EXPANSION

Hi, I have a bit of knoledge on programing gals, not to much, but enought to program by myselft a gal for memory expansion. If you provide me the schematics, I can do code to use a spare pin as enable/disable. I will also be interested in 1 of this PCB if yet available. The only problem with your d...
by Chr$
Wed Jun 29, 2022 10:46 am
Forum: General QL Chat
Topic: Vacuum forming dongles
Replies: 5
Views: 197

Re: Vacuum forming dongles

Looks awesome!. Because I clone some time ago the PCB of the cartridge (here: https://github.com/alvaroalea/QL_Rom_Cartridge not sure if is OK, because I do it from pictures of internet) I also tried to do the case, I have Mold Press from We R Memory Keepers that I think is about the size of yours,...
by Chr$
Fri Jun 24, 2022 8:30 pm
Forum: Hardware
Topic: QLUB Adapter - Initial Release...
Replies: 171
Views: 29828

Re: QLUB Adapter - Initial Release...

Just noticed the Teensy 2.0++ is discontinued.

https://www.pjrc.com/store/teensypp.html
by Chr$
Thu Jun 23, 2022 10:16 pm
Forum: Hardware
Topic: DIY RAM EXPANSION
Replies: 98
Views: 45406

Re: DIY RAM EXPANSION

Hi Chris! Looks great :-) As for a 'disable' feature, I have done this before (for a very different RAM Expansion design) by allocating a pin on the GAL for the purpose and adjusting the decoding logic to take account of the state of this input. Happy to share my (far inferior) design via PM, shoul...
by Chr$
Thu Jun 23, 2022 3:49 pm
Forum: Hardware
Topic: DIY RAM EXPANSION
Replies: 98
Views: 45406

Re: DIY RAM EXPANSION

Digging up this thread again because I had some internal RAM PCB's made based on the design/discussion here but using SMD RAM chip and GAL, so that it can be fitted without having to change the CPU socket and without rubbing up against the ZX8301. A mistake was made on the PCB and one of the GAL pin...
by Chr$
Wed Jun 22, 2022 8:55 pm
Forum: General QL Chat
Topic: Vacuum forming dongles
Replies: 5
Views: 197

Vacuum forming dongles

I got a vacuum forming machine (a small model aimed dentists). Plastic sheets 130x130mm fit inside and that's just about enough to practice replicating some original ROM dongle/kludges, which are of course vacuum formed in the first place. Making the master from the inside of a real dongle was quite...