HC533 Amiga 500 R6A Fast RAM issue

Pkdc

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Jul 31, 2016
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Anybody have an idea why my HC533 card takes the 512K trapdoor RAM card (AmigaKit) and adds it to the 8 mb Fast RAM instead of Chip RAM?
It's an Amiga 500 R6A board, Workbench 3.1

gives me 1 MB chip ram without HC533 card installed

Thanks!
 
Check the address of the memory ranges with Xoper, ShowConfig, or SysInfo.

ChipRAM (512K) is $00000000 to $0007FFFFF
ChipRAM (1MB) is $00000000 to $000FFFFFF. $00800000-$000FFFFF is the remapped Ranger memory noted below.

The HC533 FastRAM should be AutoConfig $00200000-$009FFFFF - 8MB FastRAM

If the trapdoor memory is reverting to Ranger-space, it will show up at $00C00000 to $000C7FFFFF. This is probably what is happening.

Something could be shorting out one of the two jumpers that alter the Ranger memory (which maps in as ChipRAM when set correctly) resulting in 1MB ChipRAM. Depends on the motherboard rev, but the basics are 1x 3-pin jumper switches it's position (all Revs or the non '+' A500 with 512K on the motherboard), and a second pad (on Rev 6, 8) or a trace gets cut (Rev 3, 5) to open a line by the trapdoor.

The OS detects the ChipRAM or the Ranger address memory with a test at KS boot time.

I've not heard any issues like this and have not encountered it with my two A500's and HC533's when it was in them.
 
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