Open Source 68K Accelerator Project(s)

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terriblefire
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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 04, 2016 9:50 am

DTACK is an input on my board. :/ I'll try the other board incase there is a silly short or something.

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Re: Open Source 68K Accelerator Project(s)

Postby czietz » Sun Dec 04, 2016 10:15 am

terriblefire wrote:The only means i have to post analog traces are in video form.


You could always do an old-fashioned screenshot in its literal sense. Any digital photo will be more readable than a Youtube video. Stuff like the potential "wiggling" of the DTACK line of course won't be visible in purely digital logic analyzer traces ... but may prove helpful nonetheless.

Although the proper retro way of course would be using this optional screenshot function for scopes: :)
screenshot.png
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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 04, 2016 10:27 am

Ok.... i have never got on with forums and photos...

https://www.dropbox.com/s/3idyccfvanvfc ... 4.JPG?dl=0

Attached image... Top to Bottom

Channel 1 /IACK
Channel 2 /DTACK
Channel 3 /DS
Channel 4 DE (MFP Pin 20)

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 04, 2016 10:37 am

terriblefire wrote:Ok.... i have never got on with forums and photos...

https://www.dropbox.com/s/3idyccfvanvfc ... 4.JPG?dl=0

Attached image... Top to Bottom

Channel 1 /IACK
Channel 2 /DTACK
Channel 3 /DS
Channel 4 DE (MFP Pin 20)


Also note that the CPLD cant drive DTACK that high. Its 3.3V.

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Re: Open Source 68K Accelerator Project(s)

Postby czietz » Sun Dec 04, 2016 10:59 am

OK, for reference a logic analyzer trace I just captured on my 1040STfm's MFP.

mfp-iack.png


I only have an 8 channel analyzer, but you can still see how it's supposed to work: In this case the keyboard ACIA generates an interrupt: I4 goes low at the left side of the screenshot. The MFP signals an interrupt to GLUE: /IRQ goes low. The GLUE will then interrupt the CPU. After a while the CPU starts interrupt processing: the GLUE will recognize this and drive /IACK low while /DS is also low. The MFP puts the vector number 6 (D2..D0 = 110) on the bus and and drives /DTACK low -- at the right side of the screenshot.
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Re: Open Source 68K Accelerator Project(s)

Postby czietz » Sun Dec 04, 2016 11:09 am

I wonder if you're ending the bus cycle prematurely. As you can see from my screenshot, it takes about 1 µs for the MFP to respond to /IACK by asserting /DTACK. Of course the CPU has to keep /DS low all that time. In your case, I see /DS going up again after maybe 250 ns.

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 04, 2016 11:35 am

czietz wrote:I wonder if you're ending the bus cycle prematurely. As you can see from my screenshot, it takes about 1 µs for the MFP to respond to /IACK by asserting /DTACK. Of course the CPU has to keep /DS low all that time. In your case, I see /DS going up again after maybe 250 ns.


Ok thats a line of enquiry thanks.

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Re: Open Source 68K Accelerator Project(s)

Postby ijor » Sun Dec 04, 2016 11:57 am

terriblefire wrote:Attached image... Top to Bottom
Channel 1 /IACK
Channel 2 /DTACK
Channel 3 /DS
Channel 4 DE (MFP Pin 20)


I am starting to repeat myself. Please post a digital trace, include at least ALL the MFP control signals including the MFP clock.

czietz wrote:I wonder if you're ending the bus cycle prematurely. As you can see from my screenshot, it takes about 1 µs for the MFP to respond to /IACK by asserting /DTACK. Of course the CPU has to keep /DS low all that time. In your case, I see /DS going up again after maybe 250 ns.


Yep. Something seems wrong there. But it is not only DS but IACK as well. It would seems that the CPU is ending the bus cycle for some reason ...

But once again, a full digital trace ... please.

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 04, 2016 6:10 pm

I've solved the issue.

Problem was my utter incompetence. Rendering a 3 min video of self humiliation right now.

EDIT: A full digital trace was not possible. I wasnt going to solder 48 wires onto the MFP.

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Re: Open Source 68K Accelerator Project(s)

Postby ijor » Sun Dec 04, 2016 6:51 pm

terriblefire wrote:EDIT: A full digital trace was not possible. I wasnt going to solder 48 wires onto the MFP.


Why you need to solder wires for performing a trace ??? Don't you have grabbers/probes? And I said control lines only, not the data and address buses. Just the full set of the control signals :)

Anyway, I'm glad you solved the issue.

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 04, 2016 9:17 pm

ijor wrote:
terriblefire wrote:EDIT: A full digital trace was not possible. I wasnt going to solder 48 wires onto the MFP.


Why you need to solder wires for performing a trace ??? Don't you have grabbers/probes? And I said control lines only, not the data and address buses. Just the full set of the control signals :)


Problem with the grabbers is they're only good for about 3-4 grabs before they stop grabbing and ping off when someone walks. I am planning a video where i burn those probes (probably with petrol or some gunpowder). It was the reason i created the 020 breakout board (and i have the 030 breakout on order already before i have finished the 030 board design.)

Anyway, I'm glad you solved the issue.


Many thanks. Without some help in thinking I wouldn't have got this.

IMG_5622.JPG


This is what the IACK cycle should look like.

Cheers
Stephen
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Re: Open Source 68K Accelerator Project(s)

Postby ijor » Mon Dec 05, 2016 12:32 am

terriblefire wrote:Problem with the grabbers is they're only good for about 3-4 grabs before they stop grabbing and ping off when someone walks.


Man, you must be using low quality grabbers. Good ones last last for many years.

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Mon Dec 05, 2016 1:35 pm

ijor wrote:
terriblefire wrote:Problem with the grabbers is they're only good for about 3-4 grabs before they stop grabbing and ping off when someone walks.


Man, you must be using low quality grabbers. Good ones last last for many years.


I break everything. Nothing ever works for me.. My motto is "if it can go wrong it will probably go on fire too".

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Re: Open Source 68K Accelerator Project(s)

Postby Methanoid » Mon Dec 05, 2016 7:16 pm

Hence the name... Has anyone enquired about manufacturing these when its finished?

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Tue Dec 13, 2016 10:43 pm

Quick update. I have finished routing the 030 board. I was slowed down by a chest infection which had me bed ridden for a week. Going to do a few checks then its time to get the rev 1 030 made by dirtypcbs.

Board has is an evolution of the 020 board but has the following upgrades...

68030 ...

FPU (PGA -> PLCC Socket) slot with CPSENSE wired up (so the FPU is detectable by the CPLD). The FPU is full 32 bit.

2Mb Static RAM 32bits wide (the CBREQ and CBACK pins are available to one of the 2 CPLDs). Its been wired for Zorro II but the CPLD could be flashed to make its location perm on the ST.

IDE Interface in the Amiga 600 style. The address it decodes to is configurable in the CPLD (Available address pin mask is 0xFF0300) (not sure if this is map-able to the ST IDE interface space or if the byte swap will cause issues).

It has 2 schmitt trigger buffers. One for each clock line.

I also added stand off holes to keep the board from tipping out of its socket under its own weight.

The idea here is to give me something to develop from so there are a bunch of features on a 10cm x 10cm board. I had originally thought of using a single TQ100 CPLD but this is harder to solder for a novice than 2 64VQ chips. I may change this in later designs

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 18, 2016 4:04 pm

The revision 3 020 board arrived. I built it and I have now published the sources at

https://github.com/terriblefire/tf520

This includes the fixes I needed for the Atari ST.

Enjoy,
Stephen

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 18, 2016 10:21 pm

You can buy the 020 boards (bare) from DirtyPCB at this link

http://dirtypcbs.com/store/designer/...sl520-rev3-zip

However the 030 boards will also be available in a month or so and they have many more features.

I am also now designing an 040 board for the A500 but it has the same level of features as the 020 board. It will focus entirely on bus protocol development (NO RAM, IDE etc)

Sneak preview of the 030 board completely routed...

Untitled.png


And the 040 board in development....

540.png


Very early days on the 040 board.


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Re: Open Source 68K Accelerator Project(s)

Postby exxos » Sun Dec 18, 2016 10:22 pm

Can you benchmark a 020 and 030 at 8mhz then with GB6 ? http://www.exxoshost.co.uk/atari/last/GB6/index.htm

Would be interesting if you can test with the caches off aswell..
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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 18, 2016 10:46 pm

exxos wrote:Can you benchmark a 020 and 030 at 8mhz then with GB6 ? http://www.exxoshost.co.uk/atari/last/GB6/index.htm

Would be interesting if you can test with the caches off aswell..


At the moment the 020 board doesnt work with the floppy drive. Actually it doesnt with the plain 68K either (and i've been ill, have building works going on and i'm starting a new business 4th Jan.)

I may need to find alternative storage mechanisms. I recall i used CART ROM emulation when i was bringing up my Verilog Atari ST. How hard is that?

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Re: Open Source 68K Accelerator Project(s)

Postby exxos » Sun Dec 18, 2016 10:51 pm

You can run stuff from the cartridge slot, but its limited (IIRC) to 128K and can't run much other than the diagnostics cart itself. There is ultrasatan which is a SD storage device which just plugs in, though if you have problems with the DMA circuit then that may not work either as the DMA does floppy and hard drive.

Might be easier to just get a new motherboard ? When things start getting "silly" I don't bother to fault find anymore when can get a new board for normally about £10-20 off evil bay.
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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Sun Dec 18, 2016 11:00 pm

exxos wrote:You can run stuff from the cartridge slot, but its limited (IIRC) to 128K and can't run much other than the diagnostics cart itself. There is ultrasatan which is a SD storage device which just plugs in, though if you have problems with the DMA circuit then that may not work either as the DMA does floppy and hard drive.

Might be easier to just get a new motherboard ? When things start getting "silly" I don't bother to fault find anymore when can get a new board for normally about £10-20 off evil bay.


Indeedy. I may simply stop for xmas and pick up in the new year.

Exxos, I'm happy to send you one of these boards populated (except CPU) if you want.

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Re: Open Source 68K Accelerator Project(s)

Postby exxos » Mon Dec 19, 2016 8:33 am

terriblefire wrote:
Indeedy. I may simply stop for xmas and pick up in the new year.

Exxos, I'm happy to send you one of these boards populated (except CPU) if you want.



OK deal , always up for fiddling with stuff 8)
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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Mon Dec 19, 2016 6:49 pm

Send me your address via PM and i'll post one tomorrow.

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Re: Open Source 68K Accelerator Project(s)

Postby terriblefire » Mon Dec 19, 2016 10:08 pm

Thanks. I built you a new board this evening. Tested it on an A500+ (because thats what was set up) and i'll post tomorrow. I'll throw in the parts for a breakout board. I dont have time to assemble :)

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Re: Open Source 68K Accelerator Project(s)

Postby exxos » Mon Dec 19, 2016 10:27 pm

terriblefire wrote:Thanks. I built you a new board this evening. Tested it on an A500+ (because thats what was set up) and i'll post tomorrow. I'll throw in the parts for a breakout board. I dont have time to assemble :)


Awesome thanks, something to fiddle with :cheers:
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