I need your help for my Falcon030

[silversword31]

Hi everybody,
I'm new in this forum and i need your help to repair my Falcon030. My falcon don't boot with the wellknown black screen and garbage graphic artefact. I own a 34ch usb logic analyzer and i've made some capture. The cpu meets a double bus error on bad memory access. On the capture, i can see the double bus error :

sqwp.jpg (130.08 KiB) Viewed 3938 times

The CPU init seems to be correct:

b0fk.jpg (105.12 KiB) Viewed 3938 times

But on the following capture, i can see that the reading of data is inconsistant. The data values change during access (don't worry about 100ns capture rate, the result is the same with 8ns rate):

wkbo.jpg (120.79 KiB) Viewed 3938 times

I think that the problem is the Combel. What do you think ?
Thanks for your help

[terriblefire]

can you export that as a vcd file?

[silversword31]

I don't know... I have to see if the software allows that...

[silversword31]

My software allows that but i don't have any save with exploitable datas and i've removed my test workbench as it was on the living room table

[terriblefire]

Well a sequence of instructions happens then the machine tries to access FE0008 and since nothing lives at that address it never gets an ACK and then it bus errors after 100 cycles or so.

So I need to see in more detail whats going on to tell you why its gone nuts..

[silversword31]

Hi,
i've another capture on cold start (tigger on vcc). I don't understand how i can have cpu activity without clock... Is the expansion bus directly connected on 68030 ?

2log.jpg (509.4 KiB) Viewed 3940 times

[terriblefire]

Can you attach images to your post rather than externally link. That looks pre reset to me as the clock is still settling down

[silversword31]

Ok, i'll use forum attachment for the future capture I've read that the 2 first long words (in $000000 and $000004) are shadowed from ROM. Is the combel do that ?

[Icky]

@silversword31, I have sorted out your photos from link to uploaded image on the forum for you.

[silversword31]

@Icky Thanks a lot