exxos's Atari, Amiga & retro forum

terriblefire wrote: 20 Jul 2020 22:13 Put the scope on the 030 CLK vs the 8Mhz clock.. they should be in sync and squared off until it hits fastram.

Wheres the easiest place to stick a probe on the 50mhz clock?

PhilC wrote: 21 Jul 2020 08:25 Wheres the easiest place to stick a probe on the 50mhz clock?

on the CPU socket... And remember its not 50Mhz most of the time.

terriblefire wrote: 21 Jul 2020 08:41
on the CPU socket... And remember its not 50Mhz most of the time.

So just to confirm what I'm looking for, an in sync 8mhz signal between the two clocks until it switches to fastram.

I'll take a look when I get home later, thanks.

I saw clock switching just sitting on desktop, so its not constant 8MHz ?

exxos wrote: 21 Jul 2020 13:17 I saw clock switching just sitting on desktop, so its not constant 8MHz ?

Yes I Guess I can switch that off for The purposes of testing. It switches fast when AS is disasserted

@exxos @terriblefire heres the two clocks blue is motherboard clock and yellow is on the 68030 before fastram kicks in.


Are the two clocks supposed to be in phase?

Whats looking bad is the presumed 50MHz cycles which look like the scope probe are loading it to much. looks like you are on x10 already though ?

exxos wrote: 22 Jul 2020 16:12 Whats looking bad is the presumed 50MHz cycles which look like the scope probe are loading it to much. looks like you are on x10 already though ?

Yes, new probe freshly calibrated too.

Putting 200pf on clk to gnd makes it get to ram check but it crashes after a lot of Xs

PhilC wrote: 22 Jul 2020 16:26 Yes, new probe freshly calibrated too.

Putting 200pf on clk to gnd makes it get to ram check but it crashes after a lot of Xs

It does look like the 8MHz is inverted :shrug:

EDIT

Actually I don't think it is...

EDIT2:

Did you try 1K pull up on 8Mhz. ?

@exxos not inverted, i tbink out of phase slightly

Edit, didn't try pullup but will now. As well of 200pf or by itself?