Centurbo 1 evolution 3b -> CT60 booster

[foft]

I'm going to upgrade from a CT1 evolution 3b to a CT60 in one of my Falcons. This topic is just to document what I needed to change, so that others can see how if needed.

CT1 evolution 3b
Firstly I looked at the CT1 docs from dev docs to see how it is set up (search for centurbo on https://docs.dev-docs.org/). In summary:
CT1 board:

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  Left AC pin:
    Connect to U24 ACIA(EF68B50) pin 3/4 - cut from motherboard
  SW pin:
    To a switch to turn turbo on/off
  SC:
    Connect to R221 pin rear side
    (FPU clock pin 11 - I did this)
  FPU:
    Connect to FPU clock pin 11 - If 50MHz capable
  YM: 
    U17 Chip audio (YM3439) pin 26 (BC1/SNDCS from COMBEL - I think this an INPUT to CT1)
  V2:
    Videl EXT video pin
  DSP:
    U38 DSP pin 74
  Right AC pin:
    U52 ACIA(EF68B50) pin 3/4 - cut from motherboard
  CLK in:
    L102 NVRAM end
  LL
    L102 pad other end (NC to L102 itself...)

Motherboard:

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  FPU clk disconnect from board clock
  U68 pin 3 - U44 pin 23
  U68 pin 6 - U44 pin 14
  NB: U44 pin 14 and 23 are BENT UP
  L102 - cut NVRAM side and connect to CT1 clk in, other end short wire to LL 
  R222 - remove and short
  R221 - remove - on back side connect SC
  R216 - verify 33ohm (330...)
  R216 - back side to FPU pin 11 - if only 25MHz capable FPU
  U37-U38 - cut trace, then need to connect to DSP wire from CT1
  U44 - replace with CT1 version! What are the changes?
  U68 - replace with CT1 version! What are the changes?
  Plugged into U63 and U63 is on the centurbo

Notes:

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  ACIA pin 3/4 is RX/TX clk
  U44 pin 14 was originally addr7
  U44 pin 23 was originally addr6
  U68 pin 3 was originally XAS
  U68 pin 6 was originally XDSP

CT1->CT60
Then looking at the other end, the CT60 install with solder connections (https://mikrosk.github.io/ct60tos/ct60/ ... t_sold.htm):
A lot is the same changes, so there shouldn't be so much to do.

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De-solder wires from CT1.
Remove the CT1 itself and put back U63.
Disconnect wires between U44 and U68.
Keep custom U44 and U68 custom GAL image (or back them up... are they protected? Don't forget to bend down the pins if doing that, or re-using them.)
Replace U44 and U68 with original GALs (or flash with these: https://exxosforum.co.uk/atari/mirror/powerphenix/rodolphe.czuba.free.fr/Museum/F030_GALs.zip)
SDMA U36: Add termination resistor 47ohms from clock trace to pin 14 of U20 (AJAX) - and maybe 26pF parallel capacitor if needed to fix SDMATEST.
32MHz DSP oscillator: Connect to Videl pin 14 (ext clk) via 33ohm resistor. Then onto FPU clk (see below).
Most CT1 wires need removing, but some are to be replaced with CT60 header wires. So worth doing that at the same time since the locations are clear. This is the case for:
i) DSP clk (trace already cut, scraped to allow soldering)
ii) ACIA clks (pin 3/4 already bent up)
iii) L102 ->CT1(33MHz in)/L102 empty pad(boost clock out)
Also for the FPU clk we can re-route/reuse the CT1 wire to connect to videl pin 14.
Put back 33ohm on R216, R221 and R222 (was shorted)
Use the CT1 switch for 030/060 mode.
Finally for power I prefer to wire it up to the Falcon power input, rather than using the floppy output to feed power in!

Warning: The Atari VGA adaptor ground VIDEL pin 14, so with this wiring we'd have no SDMA clock with that!

[Steve]

Sounds like the original booster accelerates the DSP, FPU and Video? Personally if I had to choose between a ct60 and that, I'd choose the boosted DSP/videl. (Higher resolutions available on desktop, better performance in DSP apps, ace tracker etc) I guess I'm just saying make sure it's worth all that work. My personal experience of putting a ct60 in an unaccelerated Falcon was very disappointing. (As an example, right now you can listen to 50khz ace tracker, without any hiccups or issues. With a stock falcon and ct60 you don't have the power to listen to anything above 33khz)

[foft]

With the CT60 ‘with solders’ install it boosts the Falcon as follows:
FPU: 32MHz
VIDEL: 50MHz and 32MHz
DSP: 50MHz
Bus: 25MHz

With the 060 off I think it turns the booster off, but I read that it’s possibly to leave the booster on in 030 mode with some creative jumpers.

I actually started off with a CT63 ‘solderless’ and the CT1. This worked mostly, but I was getting some visual errors(like static) in demos. I thought this may be a more standard tested setup.

I am wondering now if it’s be a good idea to populate the booster circuit on the CT63 too…

[mikro]

Perhaps stating the obvious but having a Nemesis/Phantom-like accelerator doesn't exclude the option of having a (solder-less) CT60. They work nicely together if done properly.

Btw it's true what Steve says, accelerated data bus and DSP makes one hell of a difference. I used to have a Phantom-only Falcon for years, it basically covered all my needs except raw power (depacking, manipulation of big data etc). Now I'm on a CT60e without it, (un)fortunately I have already forgotten how it felt; just a year ago I tested my other Falcon with the Phantom and was shocked how different it felt.

[foft]

I tried to read the custom U68 and the custom U44 with the TL866II. Unfortunately they seem to have the lock bit set. I've not found these available anywhere, there is a CT1_GAL.zip, but that only has the JED for the CT1 GAL itself, not these two.

So I made a fresh U68 so I can keep these to go with the CT1. I think I might not have a 20v8, so might have to order one of those to replace U44 - checking!

It did 'mostly' work with the CT1 and solder-less CT63. The problem is that 'mostly', I guess its a slightly timing problem somewhere.

[Darklord]

Perhaps stating the obvious but having a Nemesis/Phantom-like accelerator doesn't exclude the option of having a (solder-less) CT60. They work nicely together if done properly.

Btw it's true what Steve says, accelerated data bus and DSP makes one hell of a difference. I used to have a Phantom-only Falcon for years, it basically covered all my needs except raw power (depacking, manipulation of big data etc). Now I'm on a CT60e without it, (un)fortunately I have already forgotten how it felt; just a year ago I tested my other Falcon with the Phantom and was shocked how different it felt.

Exactly. My CT60 equipped Falcon has the motherboard mods, installed by Mark Ducksworth (not heard from him
in years - don't know where he is these days).

According to him, each Falcon's motherboard is different in how much acceleration it will accept on those components.

For example, in my Falcon motherboard's case (IIRC), the DSP and Videl would not accept 50mhz without causing errors. 40mhz
was as much as he could squeeze out of it. I can't remember if the others topped out at 25mhz, seems like that number pops up
in my head...

Probably not related but I can't go higher than 95mhz on the CT60. At 100+, I get strange graphical glitches (random) and some
soft crashes. Shame that, always wanted to say I had a triple-digit Falcon. :)

And yes, it bloody well does make a big difference! :lol:

[foft]

I’ve been trying to find any details on the modified U44 and U68 gals. The only thing I found was a reference to bugs in the Atari gals from Rodolphe.

Probably it can be tested, since it’s probably only a small modification from the Atari versions, which have the logic available.

I did find this, which fiddles the voltages to read protected gals, which is pretty neat.
https://gitlab.com/MHeinrichs/galdurino

Oh one more thing regarding high frequencies on the 68060 rev 6. Mine seemed stable at 100MHz but I found with fputest that some instructions fail at >94MHz. Of course trig always fails..

[mikro]

If you want, write me exactly what do you need from Rodolphe, which gals, what format etc, he's usually very open to provide me with any files I ask him about.

[foft]

If you want, write me exactly what do you need from Rodolphe, which gals, what format etc, he's usually very open to provide me with any files I ask him about.

That would be fantastic Mikro. Please could you ask this:
In the Centurbo 1 Evolution 3b installation document it says that replacement GALs for U44 and U68 are provided. Do you still have the JED(or LCR/GAL) for the replacement debugged U44 and U68? If not, do you recollect what change was done from the original Atari version?

[foft]

On the CT60 installation side, the good news is it works. No more video glitching like I had with the mix of the CT63 and CT1.

Though, as with all things Falcon, you fix one thing you break another:-) The RAM test is failing in 060 mode, whether boost is on or off. Perhaps I need another wait state for some reason?!