CURRENT PROTOTYPE STATUS (SEC 64MHz 68000)

[exxos]

What I did just is to use GLUE decoding and GLUE DTACK for ROM. I had to use the PLD ROM decoding with ST_DTACK to allow it to use the DTACK from the GLUE during a ROM address... anyway, that worked! The only difference is that I used the DTACK from GLUE not from my generated PLD code. So DTACK is being issued with my PLD code when the GLUE decode doesn't.. the plot thickens..

What this seems to be is I am decoding a ROM address which I shouldn't be, but don't see how. my DTACK code is based on the ROM decoding, so it can't issue DTACK unless the PLD decodes a ROM address..

I did disabled TOS206 decoding as well ust in case, but same issue. So its like some part of the ROM space while is actually valid for ROM space, the GLUE isn't actually decoding every address :stars: :shrug:

[exxos]

ahhhhh :lol: :lol:

So blocking the end of ROM space didn't work. So I thought to block the start of ROM space after 8x CLK8s and the error is gone!

What I did here is to only allow the start address to decode up to 8 clocks after RESET. So anytime anything tries to decode address zero again, it will not issue DTACK.. So that seems to be the issue...

Now I need to do some more testing....

[exxos]

I had a thought that I am actually issuing DTACK on any ROM access, so if something tries to write to ROM it could issue DTACK, which could well be the issue with the diagnostic cart error.

So I added RW into the ROM decoding, and now I get a new error..

I6 :roll:

err.jpg

So no idea why its doing that. Still boots to GEM desktop just fine. EMUTOS now saying Illegal instruction.. then address error. :shrug: :shrug:

EDIT:

So the diag-cart error is gone if I let the CPU set ST_AS on ROM WRITE... bizarre..

So now EMUTOS loads the PRG, but locks up on the green loading screen, like the PRG loads and nothing happens afterwards..

[exxos]

The round up so far then.

The diagnostic cart seems OK now.

TOS206 won't boot at 50MHz. TOS104 does...

TOS104 & TOS206 will boot and format a floppy fine at 40MHZ, BUT only if "slow TOS" (3XCLK8) delay is used on DTACK.

I can however boot GB6 with "fast-tos" as before.

With "a bit faster TOS" 2xCLK8 delays..
TOS206 formats fine.
TOS104 starts coming up that error box again.

So something craps out with TOS104 for some reason.

Moving for "fast-tos" 3x40mhz clocks..
TOS104 doesn't format.
TOS206 does format.

So, again, it looks like TOS104 has some iffy format routines.

GB6 crashes (4 bombs) on the start of any test, but loads up fine each time oddly. :shrug: It will run the GEM WINDOW test, its the only test which doesn't disable interrupts... So disabling interrupts is causing 4 bombs.. which is a problem I didn't have before :roll:

EDIT:

Fixed the GB6 crash issue thankfully!

So at least the diag-cart is behaving so at least that is some progress albeit small.

[exxos]

EMUTOS is still unhappy :(

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IMG_3764.JPG

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[exxos]

Had a thought to try a 16MHz oscillator. EMUTOS now boots, and the floppy format issue is gone. So it is the daunting task of finding out what is tripping up at higher speeds..

[PhilC]

Did it work ok at 32 or have you not tried that?

Good luck and hurry up :lol: :P can't buy one if you don't finish it.

[exxos]

Did it work ok at 32 or have you not tried that?

Not tried it. Though imagine it will still fail.

Good luck and hurry up :lol: :P can't buy one if you don't finish it.

Yeah, i'm giving it 100% time to try and get it finished. Problem is, I don't know what the problem is, so I can't solve something when I don't even know where to start. The only thing I do know is slowing ROM access does fix the floppy format problem, but EMUTOS still doesn't boot anyway. I want to say TOS104 and EMUTOS are failing to work at 40MHz, but TOS104 works in steem emulator at higher speeds.. and I am sure EMUTOS has been run at higher than 40MHz before.. but with TOS206 working fine, I still think its some software issue..

I did try some clock switching code before the V2 design died, but its not happy doing that for some reason :( I'm back using the V1 board as its the only board which is working right now. I really don't want to add clock switching on to this design seems a bit of a step backwards. But I am not really sure that would even help.

I'm getting someone else to make up one of the second revision boards for me as I am struggling soldering these things reliably myself :( I've got a few more signals I can play with on the REV2.

[BlankVector]

Damn. We will have to investigate that. I hope it's not an EmuTOS bug. However, I have never see such thing before.
Once again, be sure that no AUTO/ACC programs are loaded at startup. Best way is to tap Control key a the EmuTOS welcome screen to cancel all AUTO/ACC programs.

[exxos]

Damn. We will have to investigate that. I hope it's not an EmuTOS bug. However, I have never see such thing before.
Once again, be sure that no AUTO/ACC programs are loaded at startup. Best way is to tap Control key a the EmuTOS welcome screen to cancel all AUTO/ACC programs.

Theres nothing on the floppy at all other than EMUTOS.. I just boot with TOS104 or TOS206, goto desktop, load from A: , thats it.

But as said before, it boots in 16MHz, but not 40MHz. TOS104 seems iffy formatting a floppy, but that is what I mentioned before.. TOS206 generally seems to work OK at 40MHz. So I am still leaning towards some issue with software than hardware, but there isn't much I can do to diagnose hardware wise now.