Search found 120 matches

by marcelk
08 Dec 2018, 11:49
Forum: Hardware and software hacking
Topic: Debugging GT1 code
Replies: 2
Views: 60

Re: Debugging GT1 code

I should add: if anyone has some code that doesn't work as expected, please don't hesitate to share it here on the forum!
by marcelk
07 Dec 2018, 17:39
Forum: Hardware and software hacking
Topic: Debugging GT1 code
Replies: 2
Views: 60

Re: Debugging GT1 code

I debug in my head. Sometimes I instrument code, e.g. place values in screen RAM. But Gigatron programs are small and I rarely find a need for such instrumentation. I build them up from small parts that are easy to verify and then modify and extend. I rely heavily on git to checkpoint stable interme...
by marcelk
29 Nov 2018, 10:23
Forum: Hardware and software hacking
Topic: at67 emulator
Replies: 18
Views: 390

Re: at67 emulator

I tried to build on OS X. configure and generate with cmake OK, also make OK, but when I start the executable I get following error: Graphics::initialise() : failed to create SDL surface. Any idea what I did wrong? I've spent an evening on it before trying to crack it, unfortunately to no avail. Sa...
by marcelk
27 Nov 2018, 08:00
Forum: Kit assembly
Topic: Measuring clock wave
Replies: 5
Views: 144

Re: Measuring clock wave

In prepping the VCF slides I found I had already captured the clocks on an otherwise unpopulated board last year. Find attached.

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a.jpg (39.02 KiB) Viewed 60 times
by marcelk
26 Nov 2018, 15:38
Forum: Escape Meta Alt Control Shift
Topic: VCF Zürich 2018
Replies: 1
Views: 122

Re: VCF Zürich 2018

Just returned from Zürich from the Vintage Computer Festival, which was great meeting interesting people and making new friends. And I finally got to play Doom on a Commodore VIC-20. The Gigatron games were also popular. Actually, mine was for the most part taken hostage by children playing Snake an...
by marcelk
26 Nov 2018, 09:45
Forum: Kit assembly
Topic: Pluggy McPlugface
Replies: 2
Views: 52

Re: Pluggy McPlugface

PS/2 keyboards contain a microcontroller that, at power-on, performs a self-check called "BAT". After succesful BAT, they momentarily flash their LEDs and all is good. Some keyboards (not all) want to draw more current in this phase than is available. This may then either result in not getting throu...
by marcelk
18 Nov 2018, 22:59
Forum: Hardware and software hacking
Topic: at67 emulator
Replies: 18
Views: 390

Re: at67 emulator

Tested on Win 10, just unzip GREAT WORK! I dug up an Asus Eeepc with Windows 7 on it that has been collecting dust for years, and I managed to get it running there. Initially there was a pop-up about missing MSVCP140.dll. Instead of downloading that from a dll site, as many Internet postings advice...
by marcelk
18 Nov 2018, 20:46
Forum: Kit assembly
Topic: Measuring clock wave
Replies: 5
Views: 144

Re: Measuring clock wave

Pfew. That looks like a normal clock. I still keep that action on my list. The LED pattern is generated by the video/audio software loop. So if those LEDs are scanning back and forth, the software is operational. And with that, practically the entire board works(*). The LEDs should hop to the next s...
by marcelk
18 Nov 2018, 20:17
Forum: Kit assembly
Topic: Measuring clock wave
Replies: 5
Views: 144

Re: Measuring clock wave

This is unexpected. I would expect to see a 6.25 MHz signal, or 160 ns period (with probably a bit of overshoot/undershoot and ringing). 35 MHz is very close to the switching speed of the inverters, suggesting the crystal and caps aren't controlling the oscillation. I would first check the soldering...
by marcelk
18 Nov 2018, 19:51
Forum: Hardware and software hacking
Topic: at67 emulator
Replies: 18
Views: 390

Re: at67 emulator

This might be more a question for at76. It looks like the emulator emulates PS2 keyboard entry, but does it also work with the save/CTRL-F3 mechanism to save BASIC programs? I tried and while save seems to have done something, when I tried CTRL-F3, it didn't look like it worked. Pluggy McPlugface r...