A500 Fast RAM & IDE

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cmorley
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Joined: Tue May 28, 2019 5:46 pm

A500 Fast RAM & IDE

Post by cmorley »

I've dusted off a project I built up ages ago to work on the firmware over the last few days. Originally just 8MB fast RAM and an ATA interface I bodged a few tracks and it now supports a mild overclock.

The CPLD is a Lattice ispMACH 4256V. Code in verilog - mine, not a port of any TF code. I enjoy doing the code and debugging (even when I'm tearing my hair out).

The CPU in it is a MC68000P10 - recycled from China & might be a remarked P8 I don't know. It runs at 13.7MHz stably though 8)

Dev board:
Photo0935.jpg
Photo0935.jpg (157.07 KiB) Viewed 5725 times
Obligatory SysInfo shot:
Photo0937.jpg
Photo0937.jpg (134.36 KiB) Viewed 5725 times
edit: the shame... the date stamp on the Gerbers is 17 March 2019 :?
matt020
Posts: 292
Joined: Sun Sep 29, 2019 9:17 am
Location: West Australia

Re: A500 Fast RAM & IDE

Post by matt020 »

Just trying to work out what you've got there....

A 68010 with 8Mb and IDE, yeah?

Would it not be easier just to buy a TF534 or the upcoming TF536 ??
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: A500 Fast RAM & IDE

Post by cmorley »

Normal MC68000P10.

I'm interested in developing hardware so buying something is pointless.
matt020
Posts: 292
Joined: Sun Sep 29, 2019 9:17 am
Location: West Australia

Re: A500 Fast RAM & IDE

Post by matt020 »

Yeah thats fair enough!

Can you add a 68030 to your board? That would be awesome!

An 030, with fastmem and an IDE port would be just right for an Amiga 500!
dalek
Posts: 224
Joined: Thu Nov 08, 2018 11:03 am
Location: NSW Australia

Re: A500 Fast RAM & IDE

Post by dalek »

Looking good! You must be having fun :)

I would be stoked to ever get that far!
terriblefire
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Re: A500 Fast RAM & IDE

Post by terriblefire »

matt020 wrote: Thu May 14, 2020 3:02 pm Yeah thats fair enough!

Can you add a 68030 to your board? That would be awesome!

An 030, with fastmem and an IDE port would be just right for an Amiga 500!
There are at least 3 boards that are open source that do that. I think he wants to do his thing.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
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arkadiusz.makarenko
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Re: A500 Fast RAM & IDE

Post by arkadiusz.makarenko »

Sometimes it is just about journey, not about destination.
Do not trust people. They are capable of greatness.
~ Stanislaw Lem
terriblefire
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Re: A500 Fast RAM & IDE

Post by terriblefire »

arkadiusz.makarenko wrote: Thu May 14, 2020 6:56 pm Sometimes it is just about journey, not about destination.
Exactly. :)
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
matt020
Posts: 292
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Location: West Australia

Re: A500 Fast RAM & IDE

Post by matt020 »

terriblefire wrote: Thu May 14, 2020 4:10 pm There are at least 3 boards that are open source that do that. I think he wants to do his thing.

Ahh I getcha. In that case, nice work! Well done!
cmorley
Posts: 291
Joined: Tue May 28, 2019 5:46 pm

Re: A500 Fast RAM & IDE

Post by cmorley »

Jens has the high features end covered with the ACA500plus & terriblefire has the 680x0 covered so I am looking at something else. This dev board was initially only about fast RAM and IDE. I added some bodge wires to feed the 68K an separate clock. E and /VMA are now in the CPLD so the timers work correctly.

It boots at 16MHz but isn't stable. I don't know yet if that is my dev board, verilog or the 68K. Next is try a MC68HC000 on it. I bought some from 3 separate Chinese vendors... hopefully at least one chip will be genuine.

At the moment it is about understanding the 68K bus and the system. There is a lot of BS out there on the internet about how the Amiga works... source docs are useful but nothing beats an experiment.
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