Search found 457 matches

by sorchard
Wed May 12, 2021 10:17 am
Forum: Dragon General
Topic: pause a listing
Replies: 1
Views: 16

Re: pause a listing

shift @ on a real machine. This also pauses basic programs.

shift space does the same thing in xroar.
by sorchard
Mon May 10, 2021 8:56 pm
Forum: Discuss This Site
Topic: New Member
Replies: 8
Views: 3075

Re: New Member

Shock Trooper wrote: Mon May 10, 2021 4:47 pm Also I cannot get Home Base by Cable to run. Is there a special way to run this game, thanks.
CLOADM:CLOADM
by sorchard
Wed Apr 28, 2021 10:43 am
Forum: Uploads
Topic: Datapen
Replies: 3
Views: 106

Re: Datapen

It's possibly a better design than the Trojan pen in the sense that it detects changes in light level rather than absolute light level, which makes it less sensitive to ambient light. Other than that it was just as disappointing for freehand drawing, as it has a similar principle for detecting posit...
by sorchard
Wed Apr 28, 2021 7:57 am
Forum: Uploads
Topic: Datapen
Replies: 3
Views: 106

Datapen

Forgot I had one of these. Sadly it doesn't work on an LCD monitor.

I wasn't able to find the software anywhere so I've attached the contents of the tape.

I've created a new page in the wiki
by sorchard
Fri Apr 23, 2021 12:55 pm
Forum: Dragon General
Topic: DRAM data retention time
Replies: 9
Views: 406

Re: DRAM data retention time

sorchard wrote: Fri Apr 23, 2021 12:42 pm easier than the 32K to 64K upgrade
I meant to say that it's easier from 64K to 256K than it is from 32K to 64K.

The reason being that the 41256 DRAMs are virtually pin compatible with 4164.
by sorchard
Fri Apr 23, 2021 12:42 pm
Forum: Dragon General
Topic: DRAM data retention time
Replies: 9
Views: 406

Re: DRAM data retention time

The .bin file is actually a DragonDos binary which you may be able to put on an SD card. I've now added a cartridge rom image to the repo anyway. Yeah, the 256K machine has been kicking around for years with a rats nest of wiring in it. It's an old school banked memory style upgrade with 41256 DRAMs...
by sorchard
Thu Apr 22, 2021 10:33 pm
Forum: Dragon General
Topic: DRAM data retention time
Replies: 9
Views: 406

DRAM data retention time

Someone who shall remain nameless put the idea in my head that I may not need the 74LS785 version of the SAM in my 256K Dragon, as there is a chance the video display could refresh the memory often enough to do the job. Naturally I was curious to find out just how long the memory could last without ...
by sorchard
Thu Apr 22, 2021 7:06 pm
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 450

Re: Diagnosing a faulty CoCo2

robcfg wrote: Thu Apr 22, 2021 4:59 pm Does the Tano Dragon have the RF output?
I think it does. Not sure what channel. Worth a try to see what happens.

There are at least a couple of options for adding composite output to a CoCo 2. It's slightly more involved than a CoCo 1 but it has been done.
by sorchard
Thu Apr 22, 2021 11:14 am
Forum: Dragon Hardware
Topic: Diagnosing a faulty CoCo2
Replies: 8
Views: 450

Re: Diagnosing a faulty CoCo2

Hi Rob, How are you connecting to the TV? The signal that normally comes out of the CoCo is not just a composite signal, it's a VHF broadcast signal, meaning it needs to go to an antenna input. (I think via an impedance matching switch box in North America). Everything else you say seems to suggest ...
by sorchard
Sat Apr 10, 2021 8:28 pm
Forum: Dragon Hardware
Topic: Dragon 32 RGB SECAM and video tests
Replies: 13
Views: 662

Re: Dragon 32 RGB SECAM and video tests

Hmmm, those bars are at a higher frequency than what I had in mind, so probably not dram noise. As your photos show, that looks like the video clock coupling into the luma signal. If the noise is on the supply rails, then some bypass caps might help. I notice in the picture of your motherboard that ...