exxos's Atari, Amiga & retro forum

Here are photos of my processors under a microscope you can not see the remains of the previous name, but you can see a very similarity pay attention to the number six and two dots of paint on it are identical to all three cpu

terriblefire wrote: 01 Jul 2020 21:51 Im a bit confused about the 330 vs 536 thing...

Mostly because not only is it the same verilog code in both boards but 66% of the traces are identical. Its a literal copy and paste job.

Strange.

The A500 is a very strange beast. For example the 536 will boot at 40 MHz (80 crystal) but only on a rev5 motherboard. On rev 6 and up it just gives a yellow/red screen at boot.

I know it wasn’t intended to work at 40 but I wanted to try anyway since there are no issues on the CD32.

Plus, doesn’t it have to slow down to 7 MHz vs 14 when accessing the motherboard? That may have something to do with it. Maybe some CPUs don’t like running at 7.

terriblefire wrote: 01 Jul 2020 21:51 Im a bit confused about the 330 vs 536 thing...

Mostly because not only is it the same verilog code in both boards but 66% of the traces are identical. Its a literal copy and paste job.

Strange.

Power supplies are different between CD32 and wedges. I know it’s a different design and may be unrelated, but most had problems getting stable 50mhz even on TF534.

arkadiusz.makarenko wrote: 01 Jul 2020 21:25 Is it that CD32 is more tolerant than A500?

For some reason my post wasn't posted, I asked the same thing.

I would love to see the CPU voltage and see the ripple on a scope for both the CD32/330 and an A500/536 .

I am using a A500 psu on my TF360 CD32.
I just added a CD32 cable to the existing AMIGA one (i don't power a wedge & CD32 at the same time off it).
I did recap the psu and replace a couple of resistors which always show heat damage.

alenppc wrote: 02 Jul 2020 01:04 The A500 is a very strange beast. For example the 536 will boot at 40 MHz (80 crystal) but only on a rev5 motherboard. On rev 6 and up it just gives a yellow/red screen at boot.

I know it wasn’t intended to work at 40 but I wanted to try anyway since there are no issues on the CD32.

Plus, doesn’t it have to slow down to 7 MHz vs 14 when accessing the motherboard? That may have something to do with it. Maybe some CPUs don’t like running at 7.

The CPUs shouldnt be unhappy with 7 but the clock signal rise time on the A500 is like a fortnight. I didnt add the buffer chip from the 534 because i didnt want more clock delays and figured with my approach i'd never get metastability...

You will probably need a phase adjustment for 40Mhz on a 500. I'll maybe come back to this after I get the these 060 bugs sorted.

Do you think it would be worth trying 90mhz oscillator with the set up as it is? Or this definitely would not work?

I have some fake cpu's from time when i was overclocking ACA 1233 on A1200. I have 4 of them and 2 orginal 40Mhz.
Some of them are running at 49Mhz and rest is crashing over 45mhz.
I have not test them on TF536 yet, but if yours will run with 98mhz oscillator, than its not a big diffrence to 100mhz

Btw. I soldered one of my TF536 and it runs fine at 108Mhz (CPU-54Mhz)

This is getting off topic guys. Start (yet another) new thread about fake CPUs.

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