68020 info
2 messages in this thread
To any and all!
A friend of mine picked up a used A2620 module for Christmas this year.
As used things go, he got no documentation for it. He called me up last night
to find out if anyone I knew had the beast or at least could get him a list of
what jumpers go where. I told him I would post a message here and let him know.
So…..does anyone have a list of what jumpers do what on this board? Also, he
says that it doesn't auto config the memory area between 4 meg and 6 meg. Any
ideas? What is the last address that the Amiga can access (Hex address).
Anything anyone can tell me would be much appreciated. Thanks! Jamie
Jamie,
just put the A2620 into the processor slot and reboot. Everything should
be working ok.
The A2620 has either 4M or 2M of 32-bit RAM mounted on it, which will be
autoconfigured as FASTRAM.
So if your friend got already another memory expansion board, it should be
populated with no more than 4M or 6M of 16-bit RAM, respectively. Some of
these memory expansion boards may not be able to be configured to 6M of
RAM, though (for example the C= A2058 board can't be set to 6M).
Well, here is the Jumper configuration for the A2620:
J302 – must be installed for proper operation on 4-layer motherboards.
J200 – when in lower position, the clock for 68881 FPU will be taken
from an additionally mounted Xtal.
J301 – closed for 4M of RAM, open for 2M.
J303 – when closed, disables all RAM on the A2620.
J304 – when closed, autoboot AmigaDOS, otherwise boot UNIX
J500 – as shipped, sets RAM timing to 100 ns.
For normal operation, you must not change any of them.
– wkc – … via AP from Hamburg, Germany