Search found 441 matches

by sorchard
Sat Jan 02, 2021 5:12 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 42
Views: 2138

Re: Problems with DOS using an Y-type connection

I'm not on facebook so I've no idea what's been covered there e.g. I don't know what the 'streaming module' is. Is the /DSD signal the one that disables SAM's ls138 decoder? How is NMI presented, direct from the MSX hardware or via the CPLD? The perhaps relevant things that the MPI does is [1] buffe...
by sorchard
Thu Dec 31, 2020 12:01 am
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 42
Views: 2138

Re: Problems with DOS using an Y-type connection

But why would it be causing any issues when the DMSX2 is effectively idle? I was thinking that maybe the DMSX2 was being addressed when it shouldn't because the mpu address bus is not always valid, but as you are gating via e this shouldn't be an issue. (The DOS addresses being so similar to the DM...
by sorchard
Wed Dec 30, 2020 10:54 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 42
Views: 2138

Re: Problems with DOS using an Y-type connection

Just guessing because I know very little about any of the hardware involved... At the moment I suspect the differences between the DOS versions is down to a chance ordering of reads and writes, and/or stack contents when the hardware issue occurs. I assume nmi from the MSX side is disabled until req...
by sorchard
Wed Dec 30, 2020 3:27 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 42
Views: 2138

Re: Problems with DOS using an Y-type connection

Happy new year to you too Pere! I think the CoCoSDC uses the SCS (P2) line in the cartridge port for its address decoding which might explain why there are problems with the address range $ff56 - $ff5d: Reading $ff56 could read from the CoCoSDC and the YM2413 at the same time. (The YM2413 outputs te...
by sorchard
Wed Dec 30, 2020 11:47 am
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 42
Views: 2138

Re: Problems with DOS using an Y-type connection

Hello Pere,

My first thought is that the problem is address contention, but that would mean it's a bad idea to connect any of these devices together through a Y-splitter.

What is the memory map of the Dragon-MSX2+ ?
by sorchard
Wed Nov 25, 2020 9:11 pm
Forum: Dragon Hardware
Topic: Capture the Dragon
Replies: 4
Views: 916

Re: Capture the Dragon

That's a great start!

Looking forward to seeing nice 3d renders of the completed article :)
by sorchard
Sat Nov 21, 2020 9:03 pm
Forum: Dragon General
Topic: MaxDUINO Digital Cassette replacement
Replies: 3
Views: 569

Re: MaxDUINO Digital Cassette replacement

Never tried one myself so can't offer any insight.

Is it possible to try the known working Chuckie Egg file from the archive in the MaxDuino? Does the file need to be converted to a special format? Does the MaxDuino work with any other machine?
by sorchard
Wed Nov 18, 2020 11:44 am
Forum: Hints and Tips
Topic: Atari Joystick Adapter Build. Baby Step by Baby Step.
Replies: 26
Views: 10739

Re: Atari Joystick Adapter Build. Baby Step by Baby Step.

sixxie wrote: Wed Nov 18, 2020 10:39 am Absolutely love the 3D view in KiCad - makes you believe it could be real ;)
Looks good to me!

The 3d visualisation in Kicad is better than what we get with the £1000 software we use at work. Especially with the raytrace view:

dgn-md.png
dgn-md.png (640.38 KiB) Viewed 705 times
by sorchard
Tue Nov 17, 2020 11:13 am
Forum: Dragon Hardware
Topic: Eprom incompatibility?
Replies: 4
Views: 844

Re: Eprom incompatibility?

That is strange. The only other thing I can think of is that Vpp (pin 1) should be connected to +5V for normal read operation. Behaviour is undefined or erratic if connected to 0V or left floating.
by sorchard
Mon Nov 16, 2020 10:03 pm
Forum: Dragon Hardware
Topic: Eprom incompatibility?
Replies: 4
Views: 844

Re: Eprom incompatibility?

Hi Rob! Hope you are well.

Are you writing the image to the upper 16K of the 27256? A14 should be high as this is the /pgm pin on the 27128.

One way to be sure is to write the same 16K image to both halves of the 27256.