I need your help for my Falcon030

Problems with your machine in general.
silversword31
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Joined: Wed Jul 08, 2020 8:07 pm

I need your help for my Falcon030

Post by silversword31 » Wed Jul 08, 2020 8:25 pm

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
sqwp.jpg (130.08 KiB) Viewed 566 times

The CPU init seems to be correct:

b0fk.jpg
b0fk.jpg (105.12 KiB) Viewed 566 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
wkbo.jpg (120.79 KiB) Viewed 566 times

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

terriblefire
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Re: I need your help for my Falcon030

Post by terriblefire » Wed Jul 08, 2020 8:28 pm

can you export that as a vcd file?
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silversword31
Posts: 13
Joined: Wed Jul 08, 2020 8:07 pm

Re: I need your help for my Falcon030

Post by silversword31 » Wed Jul 08, 2020 8:31 pm

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

silversword31
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Re: I need your help for my Falcon030

Post by silversword31 » Wed Jul 08, 2020 8:46 pm

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
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Re: I need your help for my Falcon030

Post by terriblefire » Wed Jul 08, 2020 9:28 pm

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..
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silversword31
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Joined: Wed Jul 08, 2020 8:07 pm

Re: I need your help for my Falcon030

Post by silversword31 » Fri Jul 10, 2020 7:09 am

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
2log.jpg (509.4 KiB) Viewed 568 times

tuxie
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Re: I need your help for my Falcon030

Post by tuxie » Fri Jul 10, 2020 7:55 am

Looks like on your LA is a Bit missing, be sure that alle Ground wires are connected (have the same LA) on that one Picture Adresse starting with 0x7 is not what the falcon does I guess.

terriblefire
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Re: I need your help for my Falcon030

Post by terriblefire » Fri Jul 10, 2020 7:59 am

Can you attach images to your post rather than externally link. That looks pre reset to me as the clock is still settling down
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silversword31
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Joined: Wed Jul 08, 2020 8:07 pm

Re: I need your help for my Falcon030

Post by silversword31 » Fri Jul 10, 2020 5:09 pm

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 ?

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Icky
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Re: I need your help for my Falcon030

Post by Icky » Fri Jul 10, 2020 5:15 pm

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

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