Hello everyone,

Just wanted to pick some of your Amiga brains and ask whether anyone here has had any success with hardware designed for the 500 working also on the 500 plus and vise versa?

I understand that these machines are fairly similar with just a few minor differences.

Looking forward to hearing from you all here.

Regards,

George

A lot of older A500 games software needs 16-bit slow memory ("other mem"). However the A500 plus can have a maximum of 2MB graphics memory ("chip mem").

The A500+ has kickstart 2.04 and once again a lot of software requires Kickstart 1.3 (and sometimes 1.2).

So the two main causes of incompatibity are attributed to these factors.

It should be possible to fit a switch to the 500+ to select chip or ranger c0000 memory, plus a kickstart switcher can be fitted. Effectively at that point you have turned the a500+ into an ECS a500 though making the point moot.

With WHDLoad those slow-fast problems are gone. Anyone who still uses a A500 should buy Kipper2k's excellent ide/ram expansion, to make a whdload possible.

What do you mean? The a500+ has 1mb of chip ram on the motherboard, if you want more ram then you can use the trapdoor.

Right.  There was a special version of the trapdoor for the plus that contained 1MB of memory (bringing the total to 2MB of chip).  Still available?

The plus has battery on the motherboard.

Except at least original Power PC board afair, http://amiga.resource.cx/search.pl?product=power+pc
they had to release plus version for A500+

According to http://amiga.resource.cx/search.pl?product=power+pc it doesn't work on NTSC amiga's.

Huh.  They were pretty extensively marketed in the states at the time, can't recall ever hearing that before.  Weird?

Some interesting discussions!

Thanks all for your input!

I recently picked up a memory expansion unit (1MB) that was designed for the a500+ (Gigatron A500 Plus: http://amiga.resource.cx/exp/gigatron500plus) When plugged into the Amiga 500, it does not recognise the expansion.

Does anyone know whether this is a hardware incompatibility issue or a fault with the expansion card?

Haha, I like how people do things almost as if it's a test.  To intentionally see if they can break things, LOL.  

At a guess I'd say it's adding the memory into a different address range than where the A500 is looking.  It recognizes zero additional memory?  An easy test for this would be to plug it into an A500+ and see if it works correctly in that system.  I don't see much info on that card on the web, but as an alternative try to track down what address range the A500 uses (this is easy to find), what address range the A500+ uses (this might be a little harder to find), and what range that card uses (this will probably be the hardest bit of info to find).  Obviously you will need some overlap there for the card to be detected properly.

It's a stock A500, right?  Only 512K on the motherboard, no other expansions anywhere?  What version Agnus (probably won't make a difference, even OCS would see it as slow-fast ram, but still)...