Expansion Area $E00000 and TF536

68030 + SDRAM + IDE

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nospam2000
Posts: 2
Joined: Tue Jan 05, 2021 9:18 pm

Expansion Area $E00000 and TF536

Post by nospam2000 »

Hi,

I'm building an Amiga Turbocard relocator board for the A1000/A500 expansion bus.
The A1000 cannot load a modern Kickstart to its 256kB WOM so it cannot directly use a Kickstart 2.04 or 3.0 and requires an EPROM/Flash card to be able to boot with a TF536.

That's why I added a 1MB Kickstart Flash to my relocator board which maps two memory regions:
  1. $F80000 to $FFFFFF for a 512 kB Kickstart (read only)
  2. $E00000 to $E7FFFF for a 512 Expansion ROM (read/write) and it is also used for the programming of a new Kickstart
There is a jumper to swap the the memory regions and also a jumper which disables the $F80000 decoding so that an internal kickstart can be used.
That way either two Kickstarts can be programmed or one Kickstart and a 512 kB Expansion ROM at $E00000.

Both areas assert the /OVR pin to deactivate the Amiga address decoding (primarily for the Kickstart ROM/WOM) and create /DTACK themselve.
7M is synthesized as "7M=/C1 XNOR /C3".

When I try to reprogram the Kickstart using the $E00000 memory area I get an error when reading the identification of Flash Chips, so I cannot program them.

I also get no Fast RAM detected. I'm not sure if this is related therefore I'm mentioning it here, but this is another story and I'd like to look at it after solving the $E00000 issue.

Now my questions:
  • Is the TF536 using the $E00000 memory area for its own purpose?
  • Is it using any other area, e.g. $F00000-$F7FFFF?
  • Any other idea, why it doesn't work (e.g. caching could by a problem)?
Michael
terriblefire
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Re: Expansion Area $E00000 and TF536

Post by terriblefire »

TF536 uses $F00000 for 64k. There are firmware versions out there that patch the $F00000-$f7fffff region assuming its a CDTV rom.

Nowhere else is touched.
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theq
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Location: North of the Wall

Re: Expansion Area $E00000 and TF536

Post by theq »

nospam2000 wrote: Wed Mar 03, 2021 6:04 am I'm building an Amiga Turbocard relocator board for the A1000/A500 expansion bus.
Hey Michael!

I've done a similar project and I've got it working on the A1000/A500/A2000. Only modification I had to do was wiring 7MHz to expansion port pin 7.
Link to my GitHub-project page
nospam2000
Posts: 2
Joined: Tue Jan 05, 2021 9:18 pm

Re: Expansion Area $E00000 and TF536

Post by nospam2000 »

theq wrote: Wed Mar 03, 2021 12:14 pm I've done a similar project and I've got it working on the A1000/A500/A2000. Only modification I had to do was wiring 7MHz to expansion port pin 7.
Link to my GitHub-project page
I have seen your project just after I started mine.

The biggest difference between our projects is the form factor. My board can be either mounted horizontally (like your's) for the A500.
For the A1000 it can be mounted vertically with the connector on the back side (in the center of the board) so it is less than 1 inch thick.

As I mentioned above, I synthesize the 7M signal from /C1 XNOR /C3, so no need for a patch cable. Maybe this is the reason for my problem because the timing will be slightly different? I need a better Logic Analyzer.

In your github page you write "while the original 68000 CPU and Kickstart ROM still are socketed inside the Amiga".
How do you disable the internal 68000 and especially the E-Clock signal it generates? If I understood correctly /HLT does not suppress the E-clock generation.

Michael
theq
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Joined: Tue Dec 18, 2018 7:16 pm
Location: North of the Wall

Re: Expansion Area $E00000 and TF536

Post by theq »

nospam2000 wrote: Wed Mar 03, 2021 3:05 pm In your github page you write "while the original 68000 CPU and Kickstart ROM still are socketed inside the Amiga".
How do you disable the internal 68000 and especially the E-Clock signal it generates? If I understood correctly /HLT does not suppress the E-clock generation.
Disabling CPU is done by grounding 'edge connector pin 60' and setting 'socket pin 13' high via a 470 Ohm resistor (Manually handling of internal and external BR (bus request) signal).
E-clock is passed straight through 'edge connector pin 50' to 'socket pin 20'. Haven't really thought about E-clock generation. It just worked ;)
bartekmalysz
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Location: Northwich

Re: Expansion Area $E00000 and TF536

Post by bartekmalysz »

terriblefire wrote: Wed Mar 03, 2021 8:33 am TF536 uses $F00000 for 64k. There are firmware versions out there that patch the $F00000-$f7fffff region assuming its a CDTV rom.

Nowhere else is touched.
Does anyone have CDTV patched FW? Please pm
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