Upgrading Q40 to 68060 CPU

[Silvester]

It is sufficient to just be careful. Regarding the CPU socket, I was more interested in the top side, to see in which way the additional pins could best be added.

That's what I was curious about, I'll carefully remove it and take photo.

[Peter]

Before I forget it: For the 80 MHz variant (and only that one) a 1.2k Ohm resistor under the CPU clock oscillator should be added. It should be soldered at the bottom of the PCB to pin 7 and 8 of the oscillator, which are the ones on the side of the 74F74 and the 100 MHz video oscillator.

[Derek_Stewart]

Hi,

To convert a Q40 to Q60, requires a 2.4v/1.3w zenner diode to replace a wire link and fitting a LT(LM)1086CT-3.3 with heat sink.

The Q40 came with Fastpage ram, the Q60 requires EDO Ram 60ns

The Q40 had a 80 Mhz oscillator fitted the 68040 reduced the clock speed to 40Mhz.

As Peter as stated a resistor is required on the clock oscillator.

The Q60-80 had a 68LC060RC75, which is a 75Mhz 68060 with MMU, no FPU, this was overclocked to 80Mhz.

[Silvester]

Taken about one hour to coax it out 2mm with gently prizing, I think I'll leave it tomorrow as the final release is where the pins could get bent.

XC68040RC40M 02E31F

[Peter]

What kind of QLiberator issues are there? Problems with MMU? I had never problems of that kind with an hyperCache 030 on the Atari.

Not with the MMU, but with copyback cache.

[mk79]

What kind of QLiberator issues are there? Problems with MMU? I had never problems of that kind with an hyperCache 030 on the Atari.

I had a look at SMSQ/E docs but couldn't find any reference to it (it is a config item). Look into it later (probably much).

It probably sets up the MMU to repeat the first 64MB of RAM. QLiberator is known to use one or two of the uppermost bits of addresses in some cases.

[Silvester]

Before I forget it: For the 80 MHz variant (and only that one) a 1.2k Ohm resistor under the CPU clock oscillator should be added. It should be soldered at the bottom of the PCB to pin 7 and 8 of the oscillator, which are the ones on the side of the 74F74 and the 100 MHz video oscillator.

So that effectively pulls down clock for 68060 at 3V3 (but not required for 68040 at 5V) ?

To convert a Q40 to Q60, requires a 2.4v/1.3w zenner diode to replace a wire link and fitting a LT(LM)1086CT-3.3 with heat sink.

I assume with Zener pointing from power feed towards regulator (fitted into empty holes, square pad is ground) ?

The Q40 came with Fastpage ram, the Q60 requires EDO Ram 60ns.

Something I'll have to track down, I only have FPM. IIRC the original Q40 only supports up to 32MB ?

Thanks for valuable info, Peter and Derek.

[Peter]

Before I forget it: For the 80 MHz variant (and only that one) a 1.2k Ohm resistor under the CPU clock oscillator should be added. It should be soldered at the bottom of the PCB to pin 7 and 8 of the oscillator, which are the ones on the side of the 74F74 and the 100 MHz video oscillator.

So that effectively pulls down clock for 68060 at 3V3 (but not required for 68040 at 5V) ?

Not for that reason, as the 68060 has 5V tolerant I/O. The resistor just provides a better high frequency signal shape at 80 MHz.

assume with Zener pointing from power feed towards regulator (fitted into empty holes, square pad is ground) ?

Kathode at the square pad, side of the power connector. The puropse of the zener diode is to pull the 3.3V output of the linear regulator "somewhat" toward 5V during powerup. This is to avoid that any 68060 pin ever exceeds the 68060 supply by +4V or more. Which could otherwise happen during powerup, as lots of components have 5V supply.

The Q40 came with Fastpage ram, the Q60 requires EDO Ram 60ns.

Something I'll have to track down, I only have FPM. IIRC the original Q40 only supports up to 32MB ?

Yes, 128 MB RAM support is an additional modification. If you are not going to use Linux, probably not of much interest for you.

[Silvester]

Not sure I understand the 3V3 supply arrangement, referring to image in last post: Square pad in group of three pads is Ground. Square pad next to power connector is +5V. With link in place (as shown) +5V is fed to other two round pads.

For 3V3 conversion replace link with 2V4 Zener diode: cathode to +5V square pad, anode to pin 2 (Vout) and pin 3 (Vin), with ground on pin 1 (ADJ/GND) of regulator.

Edit: nonsense above

[Silvester]

BTW, Peter, if you can recall, did you make use of Presence Detect (1-4) on 72 pin SIMMs ?