DFBX1 Issues

[VadimK]

Hi!

I just installed DFBX1 and have some issues. Booting with DFBX1 enabled and TOS4.04 from flash, graphics is messed up. Atari Logo and all text output is unreadable. Booting to desktop with maprom and nvdi works. Desktop looks and works ok and most of the programs I tested runs well, TT ram is working, GEM Bench values are as expected. MINT + XaAes is working, Magic 6 freezes before it reach desktop.
I tried with Emutos in second bank and there is no problem with text output and graphics, but it doesn't see my drive. Without ability to start anything from drive auto folder its usability is limited.

BTW my configuration is:
TOS 4.01
14 MB ram
No clockpatch

Screenshot:
https://share.icloud.com/photos/0d6Fnes ... 3ICTJisHWA

[stephen_usher]

TOS 4.x VDI can't work with TT-RAM. That's why EmuTOS is required.

[VadimK]

My issue start right at boot I can't see logo, mem test, boot messages, I can't use boot manager.
As far as I know TOS4 do not initialize TT ram so there should be no problem until TT ram is initalized. I even tried to disable TT ram with jumper, but with no effect.

[exxos]

TOS404 works fine on the DFB1X.

I have never seen that corruption problem before. Seems like the blitter cannot access STram and properly for some reason. But that's a motherboard problem.

Id suggest removing your TOS401 ROM.

Also you really should have a verified clock patch.

Also does the same problem happen when you disable the DFB1X via the jumper ?

[VadimK]

Yes, it looks like blitter corruption but why would it fail accessing ST ram, I have no idea.

By removing TOS401, you mean replacing rom chip with newer 404? I can try but the only source I know about is your shop, are you still shipping to EU?

I plan to add clockpatch, but it will require help from someone with better soldering skills. So it may take a while.

With disable jumper everything works as expected.

I tried to run DFB1X at 40 MHz, erased and re-flashed both banks with TOS404 but there was no change in behavior.\

BTW Is TOS image unmodified? I was thinking about flashing some older TOS version (the only TOS I know is working with this board is installed v 401)

[exxos]

By removing TOS401, you mean replacing rom chip with newer 404?

No, just remove the chip as it will run from flash anyway. I don't recall if there is a conflict between flash and ROM, so best to remove it just to make sure you don't have a TOS401 <> TOS404 conflict.

With disable jumper everything works as expected.

Id assume the EXP clock isn't good enough to drive the DFB1X as you don't have a clock patch. But it's only a guess.

I tried to run DFB1X at 40 MHz, erased and re-flashed both banks with TOS404 but there was no change in behavior.\

Speed and flashing isn't likely the problem. The DFB1X is tested for hours doing all sorts of tests already at 50MHz before they are sold.

Have you read the DFB1X FAQ ? If your PSU voltage is low, then that can also cause issues. Recapping the PSU is a must these days also.

BTW Is TOS image unmodified? I was thinking about flashing some older TOS version (the only TOS I know is working with this board is installed v 401)

It's just generic TOS404 which is flashed by default in the flash on the DFB1X.

[Badwolf]

I'm intrigued as to what the problem is. Not having got around to repairing my second Falcon motherboard, I've yet to experiment with an accelerated system clock (I'm not brave enough to do this on my original bird).

Conceptually I can't think of an obvious reason it shouldn't' work, but then I don't know the details of these bus speeders.

The DFB1(X) clock switching logic has problems when the clock is too slow* (special handling goes into the DFB1X firmware to look for the 8<-->16 MHz clock speed switch and disable acceleration when it's at 8, but it's not perfect).

Also DFB1(X) take their clock from the expansion branch of the clock fan-out. Do these patches desynchronise these somehow?

If the booster doesn't work in no-acceleration mode (one of the jumpers set on DFB1, I think this is carried through to DFB1X), then it's possibly not logic, but physical. The clock signal going into DFB1 is extremely sensitive to being overloaded.

This would probably be quite an interesting investigation for anyone so minded and suitably equipped (Steve?), but not one I have any time for, I'm afraid.

BW

* I abuse a related clock switching circuit for two completely unrelated clocks. This is because in general it switches faster than the proper circuit and is 'good enough' in most cases, but this does introduce up to one half cycle which is at half the speed of the slowest clock. At 16MHz, this means there's potentially one 8MHz half cycle in there. At 8MHz, this is up to one 4MHz half cycle. I theorise my problems with 8MHz mode is that this 4MHz half cycle is too slow for the 030's dynamic core. I could be barking up the wrong tree, but it fits the observed behaviour.

[Steve]

@Badwolf I think you've mixed up which thread you've wanted to respond to. I assume you wanted to reply to this guy:

viewtopic.php?f=112&t=7427

The person in this thread isn't using clock boosters.

[Badwolf]

@Badwolf I think you've mixed up which thread you've wanted to respond to. I assume you wanted to reply to this guy:

viewtopic.php?f=112&t=7427

The person in this thread isn't using clock boosters.

Sorry -- you're quite right. Must have have two tabs open!

BW

[Badwolf]

I have never seen that corruption problem before. Seems like the blitter cannot access STram and properly for some reason. But that's a motherboard problem.

@VadimK

The Atari logo and text are blitted to the screen (with the blitter) from ROM. You're running TOS4.04, but copying from TOS4.01 -- the data's in a different place, so you get nonsense! The two ROMs do not conflict, but in order to work seamlessly, the two versions on the motherboard and in the flash need to be the same version.

It's a quite harmless visual artefact at this point in time, however.

If you remove the TOS4.01 from on-board, you'll find the corruption turns to black boxes instead. I wouldn't recommend this as then you remove your ability to boot with DFB1 disabled to reflash.

Your solutions are:

* Leave it as it is -- if it works fine once NVDI kicks in, you should be completely fine.
* Upgrade your on-board ROM to TOS4.04, the logos and fonts will now blit from the 'right' part of ROM.
* Flash the same version (TOS4.01) to DFB1. They'll match again, but you'll be stuck with 4.01, obviously.
* Use a modern EmuTOS build that supports true colour VDI. You'll not have to worry about any AUTO programs to get a fully working machine in this case.

Cheers,

BW