GX4000 to Plus Mod Quick Update For Those Interested

[Badstarr]

Hi all,

UPDATE! Keyboard is fully working with the exception of the DEL key, can't find any issues with the connections, only got the (dead) 464 it came from a week ago so might never have worked. No biggie I can use CLR and Cursors for now and hack up a solution later. Typing on a GX4000 is rather addictive (well it is for me! LOL!) 


While it may not be the most exciting news, I have a (mostly) functional keyboard attached to the console now! It appears I've missed something when mapping out the connections and some of the keys on the left are either DOA or mixed up, should be easy to sort out though!


As I expected, adding the keyboard now brings up the F1/F2 Menu rather than jumping straight to Amsdos and fortunately the function keys are working. So it appears that all the Function Keys are essentially all "pressed down" on boot when no keyboard is connected and the connection from the AY to the ASIC is missing hence the jump to Amsdos. This maybe useful info somewhere down the line.


I wanted to try connecting a simple connection to the ASIC to load a tape to run some diagnostics but it doesn't seem to work, will have to have a look at the schematics again to see if I've missed something.


Ah well, still making progress, just sort out the minor keyboard problem then it's time to make the disk interface!

[Bryce]

I don't think the Function keys are normally closed, that would cause even more key clashes. There are a few "non-keys" ie: unused spaces in the grid (Y10, X1 - X7), they may have shorted one of these to detect the keyboard. Or have you tested what keys are really shorted?

Bryce.

[Badstarr]

I haven't checked to see if any keys are shorted as of yet. I guess I jumped to a bit of a conclusion there, I'm guessing the keyboard connection must be relevant as the menu didn't appear until it was attached, I suppose it could be just a coincidence, I will investigate further, however, I can say that there is definitely a short from keyboard pin 10 - pin 2 on the 464 mainboard, (I could have that reversed though) I have just cut the connection on my mod and there seems to be no difference. On the other hand (almost literally), I have the left side of the keyboard working, but now the right is missing a few keys, what a mess on! It is pretty cool to be able to at least half type on my GX4000 now!