Want to make an A500 1mb expansion board
 

Hi All,

Does anyone know of any schematics for a 1MB chipmem expansion board for the A500, I'd like to make some boards up. I think there would be a demand for them ?

With the ACA500 out there's good demand now for anything A500!

Would you be making a 1mb upgrade that's fully chip Ram for A500+? These are the ones that usually carry a premium!

Hi Steve,

The a500+ is the main reason to make this so people can get the 2mb chipmem. Even if i can get my hands on an old broken one could be good enough to get the job done.

Kipper2k, you can look at the a500 and a500+ schematics, the 1MB and 2MB Agnus pinouts are explained there along with the RAS and CAS routings.

http://www.1000bit.it/support/manual...500plus_sm.pdf
http://www.amigawiki.de/dnl/schematics/A500_R6.pdf

Thanks Jope,

the first link has a schematic for a 1mb expansion. i'll check out parts availability

Ah yes, if you're targeting the A500+ then "all" you need to do is to hook up the RAM to the trapdoor slot. Add some decoupling capacitors and you're golden. ;-)

I originally thought you were going to create a 2MB Agnus adapter for the Rev6 mobo.

you know if you make it with sockets or something you could use it half populated on the 500 as well,just a thought.

yah, sockets is good, especially for repair etc

yep,makes it a tad more expensive i suppose but worth it.
you could mark the pcb sockets for population for different machines(512k and 1mb or 0 and 1),a few manufacturers used to do it this way.

And maybe RTC as an option:
0.5 MB + RTC
1 MB, no RTC

I think once the memory was done, the selectable mem/RTC config options would be simple

@kipper, I believe that in the A500 pack I sent you a while ago there was a 500+ 1 MB chip expansion as well, so you might want to check that one out.

I will release the 1mb chipmem board for the a500+ hopefully next week, it has RTC onboard (ideal for those a500+ boards that have the corroded battery circuit) and will take your A500+ to 2MB chipmem total. This board should also provide an extra 512k fastmem/chipmem to earlier revision boards... pictures to follow soon.

the board is a bit smaller than my a600 1mb board.

I also updated my webpage too. www.kipper2k.com

But not the link in your signature :-P

Me too :)

I don't know about a corroded circuit, but my A500+ simply has its battery removed. Would this expansion board give me the clock simply by plugging it in, or do I have to cut some traces first ? Remove chips... Disable the reactor...
:)

EDIT:
Ah, never mind, I've just read the description on your page. So a solder blob is in order, eh :)

Sounds cool and nice price!

Any plans on doing a A1200 FastRAM expansion w/RTC?

Thanks!

Always nice with more memory, even if on A500+ I guess you can get 1.5MB just by sticking any trapdoor expansion in?

Good initiative with the battery/RTC (modless and socketed battery?)

About the A500, is there any way you could make a 2MB board that the ACA500 tolerates? It would be yummy :)

Ive got an 1mb 500+ expansion unit, ill confirm im getting 2mb chip on the 500+ and send some photos

2mb chip on the A500 is useless
1mb chip for the A500 is enough for all games and apps

there is only 2 ECS games that requires 2mb chip ram: are "wasted dreams" and "Code name Hell Squad"

Yeah, but what about those of us who aren't game lamers and want to do stuff that doesn't fit into 1MB of chip ram? ;-)