Programming PALs

[Badwolf]

Well progress, but not fully working yet.

discprompt.jpg (128.41 KiB) Viewed 394 times

Running the program results, for the most part, in a black screen. Pressing reset brings up the following. This looks promising, but nothing further occurs. No disc drive activity, no signs of response to keyboard input.

Running the program without the card installs leads to a hang with the desktop showing, so definite signs of some life occurring there. Incidentally, running the program without the 286 installed produces that same desktop hang, so also an indication the processor is detectable.

I don't suspect data or address line shorts on the Falcon side as I get far enough to run the program, but perhaps there exist some on the 286 side, so that'll be something to check, however the reset behaviour strikes me as odd and is not what the manual says should happen, so that will probably be my first port of call.

This Falcon's reset circuit is not the best (I've investigated it before), so it's possible it's connected.

The 'scope will have to come out!

BW

[tOriman]

Hi Badwolf,

It is strange that you have problems with FalconSpeed clone

Two things to check again:

Did you solder the GALs correctly? It's all about the order. The files on my www are numbered as in the picture - 1, 2, 3, 4.

fs_tori.jpg (36.7 KiB) Viewed 335 times

Are you sure your 286 is OK?

Best regards
tOri

[Badwolf]

Hi Badwolf,

It is strange that you have problems with FalconSpeed clone

Two things to check again:

Did you solder the GALs correctly? It's all about the order. The files on my www are numbered as in the picture - 1, 2, 3, 4.

fs_tori.jpg

Are you sure your 286 is OK?

Best regards
tOri

Hi tOri,

I've not found the culprit yet. I am starting to worry I've messed up the GALs. The numbering I put on them has washed off in the cleaning process, but fortunately I have video, so I'll review that.

...however it's not all bad news. In for a penny, in for a pound: I built two boards. The second didn't work at all, but in a head-smack moment I noticed I'd soldered on IC10 backwards and reversing that fixed it beautifully!

Now that I've seen a working one, I know that there is meant to be flashing cursor which mine doesn't have (also the working one doesn't require the reboot after first running the program). Hopefully that's a clue. Interrupts, perhaps?

Cheers,

BW

[Badwolf]

Success on both boards!

I think there were some dry solder joints on the PLCC GALs. I was a bit new to the soldering J-leads game and hadn't appreciated how much solder I could safely lash on.

Now I only need to figure out how to get a hard disc to work... 5 to 16MB only! My Bluescsi block device very unhappy (corruption all over the place). Need to try to find a spare SD card to try on IDE.

BW

[tOriman]

GRATULATIONS BADWOLF!

Please contact Kroll - he knows more about FalconSpeed and HDD

Best regards
tOri

[Badwolf]

GRATULATIONS BADWOLF!
Please contact Kroll - he knows more about FalconSpeed and HDD

Thank you very much for reverse engineering it & publishing the results!

I wanted a Falcon speed back in 1994 or thereabouts. I didn't get it. Now I can play with it, but the hard disc is very much needed! I'll start a new topic and flag Kroll.

Cheers!

BW

[tOriman]

I'm happy you love it

tOri