From simple AZERTY Falcon project to custom ARM bus master - advice needed please

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foft
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by foft »

So I received the 68030FE CPU and also the solder mask/uv lamp to fix some broken pads.

The uv solder mask/uv lamp wasn't a big success! I managed to cut some very small copper pads and tried to 'glue' them with this. Which was misguided since of course its not glue, just there to stop the solder! So I then used a combination of epoxy from the store and solder mask for edges. This was also a bad idea since the generic epoxy melts and then the pads fall off when soldering to them. I read on eevblog that some people had success with Chemtronics CW2500 (high temp epoxy - https://www.digikey.ch/en/products/deta ... 00/1929217), despite being an 'overlay'. I might give that a try unless anyone has a better idea? Also I didn't find a cheap 'circuit frame' with replacement pads, so am cutting them with a craft knife.

In any case I didn't really need to repair these pads (except one...) since they are not connected pins. So I soldered on the 68030 anyway. I think its all soldered properly, I double checked a few times under the USB microscope (on a boom arm...). It is somewhat alive, I see AS, LDS and UDS go a few times on the logic analyzer. I also see a valid function code (I think - need to double check). However VIDEL does not lower DTACK, instead I get BERR lowered a little later. This definitely works with the FPGA as a host so there must be something bad with the 68030 soldering I'm not seeing rather than a VIDEL issue. Perhaps an invalid address?

In the meantime I got another working Falcon so I have something to compare with. It had an Eagle Sonic 32MHz on it, which crashes when I run the 32MHz program! I need to find the installation instructions for that (dev docs has the version with ram but not this one - as far as I can see) and back it out I guess. Then I'll have a working unit to measure/compare signals on which'll be super helpful.
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by exxos »

foft wrote: Tue May 10, 2022 9:00 pm In the meantime I got another working Falcon so I have something to compare with. It had an Eagle Sonic 32MHz on it, which crashes when I run the 32MHz program! I need to find the installation instructions for that (dev docs has the version with ram but not this one - as far as I can see) and back it out I guess. Then I'll have a working unit to measure/compare signals on which'll be super helpful.
Probably won't help..but... https://www.exxosforum.co.uk/forum/viewt ... =10#p80225
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
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atari030
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by atari030 »

I had an Eaglesonic Falcon years ago and it would crash running the 32Mhz program if I used HDdriver. ICD worked flawlessly. If you are running without an HDD I guess you can disregard that. I may still have the instructions buried somewhere.
foft
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by foft »

Aha, yes there are 3 hard drives and a cd rom in this falcon. So that sounds likely the culprit. If you could dig out and post the instructions that’d be awesome.
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Badwolf
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by Badwolf »

foft wrote: Tue May 10, 2022 9:00 pm This definitely works with the FPGA as a host so there must be something bad with the 68030 soldering I'm not seeing rather than a VIDEL issue. Perhaps an invalid address?
Do you mean VIDEL here, or COMBEL?

The Falcon will boot up in 8MHz until TOS instructs COMBEL to switch to 16, so it's nice and slow to debug initially. You should be able to monitor the first few access on the address and data ports (via the expansion heaer).

First few addresses should be 000000, 000002, 000004, 000006.

The corresponding Data should obviously be 602e 0404 00e0 0000.

Obviously with those values it's hard to see stuck address lines, but stuck data lines shjould be easier. Is it getting past those first four?

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
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foft
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by foft »

Yeah I meant COMBEL, was sleepy!

It actually gets stuck on the first access. I’ll check the address etc is correct.
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Badwolf
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by Badwolf »

foft wrote: Wed May 11, 2022 5:30 pm Yeah I meant COMBEL, was sleepy!

It actually gets stuck on the first access. I’ll check the address etc is correct.
You may not think it now, but that's probably a good sign! Hopefully it's something simple and then it'll work. Also, it means we can probably forget the data lines for now.

If it gets part-way through then you're into a mess! :lol:

Easiest thing to do before even hitting up the probe, I suppose is to use the expansion port (again) and do continuity checks on the pins. Only GND and VCC should have any other pins shorted.

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
foft
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by foft »

Well I captured the address lines with my logic analyzer. It only has 8 wires so it took a while since I was also capturing clk, as and reset so I could align them. I think that part is working.

So back to the FPGA on the expansion port. Since I had the FPGA set up for that I decided to use that to monitor the pins with its built in logic analyzer (signal tap). Not quite got that working yet entirely, but I can see AS and the data lines. I do indeed see those numbers:
602e
0404
00e0
0030 (not 0000?)
...(unstable)
46fc
2700
3038
8006
3038
8006
4e70 <- think this is the reset instruction
3038
ea00
8006
31fc
... then reset goes low
Now I'm pretty sure I remember the rom has a 'reset' in fairly early in boot. So it does seem to be partly working.

However I don't see address lines or dtack or berr go low, or fc. I guess some signals are optimised out in the fpga core build!

Anyway, some puzzles to solve for the coming days! I guess if I get this logic analyzer running better I can see more. Now if only my SOCkit board didn't reboot after every time I use signaltap - that is really annoying!
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Badwolf
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by Badwolf »

foft wrote: Wed May 11, 2022 10:09 pm 602e
0404
00e0
0030 (not 0000?)
...(unstable)
46fc
2700
3038
8006
3038
8006
4e70 <- think this is the reset instruction
3038
ea00
8006
31fc
... then reset goes low
Now I'm pretty sure I remember the rom has a 'reset' in fairly early in boot. So it does seem to be partly working.
That all sounds bang on to be honest.

I think you're plenty far enough through the boot process that the diagnostic cart can come out to play. Wire up serial at 9600 on the DE9 port and see what you get. :)

BW
DFB1 Open source 50MHz 030 and TT-RAM accelerator for the Falcon
DSTB1 Open source 16Mhz 68k and AltRAM accelerator for the ST
Smalliermouse ST-optimised USB mouse adapter based on SmallyMouse2
FrontBench The Frontier: Elite 2 intro as a benchmark
ijor
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Re: From simple AZERTY Falcon project to custom ARM bus master - advice needed please

Post by ijor »

foft wrote: Tue May 10, 2022 9:00 pm In the meantime I got another working Falcon so I have something to compare with.
It rains Falcons over there, Mark? :)
I then read through the service manual looking for inspiration. I saw that one of the first instructions executed on the 68030 is RESET. This does a long 512 clock period reset pulse. I implemented this and then ... I seem to be able to read and write memory. Also FF8006 is read.
That's interesting and unexpected. I'm curious if it's a problem with system hardware reset. It would be interesting if somebody that can flash a custom ROM tries a patched TOS without that CPU Reset instruction and see if the system boots and works ok.
http://github.com/ijor/fx68k 68000 cycle exact FPGA core
FX CAST Cycle Accurate Atari ST core
http://pasti.fxatari.com
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