View Single Post
Old 16 November 2014, 16:27   #934
Registered User
Join Date: Aug 2004
Posts: 2,828
Originally Posted by Toni Wilen View Post
Currently if ECS Agnus is selected with 512k chip RAM, hardware is emulated with "1M chip jumper" in enabled state and A26x0's memory detection does not handle it correctly. (If switch is added, I guess "1M chip jumper" off is better default)

("1M chip" jumper = jumper that selects if 512k slow ram is located at c00000 or 80000)

EDIT: fixes both and adds extra option.
Yes, the 1M chip jumper being disabled for 512KB chip machines makes sense because that was the factory default setting. All A500s with ECS Agnus shipped like that; adding an A501 memory expansion gives $C00000 RAM by default. [I think many/most(?) A500s which came with Kickstart 1.3 had the ECS Agnus.]
Originally Posted by Toni Wilen View Post
EDIT2: 0x01000000 memory expansion is available as a separate board (DKB 2632) and it needs addmem-type program in startup-sequence. ROM monitor expansion ram detection is only used to support 'i' command, it is not used to add the memory or use it for any other "real" purposes.
According to this page Commodore did make prototype "BigRAM" and "FastRAM" expansion boards for the A2630. The daughterboard specification is here. I assume no publically-released version of the A2630 ROM contains code to add that memory automatically.

The DKB 2632, depending on jumper settings and SIMM types used, can have several non-contiguous chunks of memory. I'm guessing the Commodore RAM board would have been in one chunk. The 2632 program tests the memory and adds it to the system list.
mark_k is offline  
Page generated in 0.06640 seconds with 9 queries