A3000T 16MB Fast + RAM on CPU card probs

[Zac67]

TjLaZer wrote:
I noticed once RAM is used up (and MB RAM is not starting to be used) it starts to crash.

Once which RAM is used up? Accelerator RAM should have higher priority and be used first. Maybe your MB RAM is just defective - try to test it with the CS in place and without. If the former doesn't work but the latter does, then there's a problem with the CS.

[Zac67]

Hmm, the accelerator shouldn't have problems with MB RAM...

You got static column or fast page? If it's SC, maybe Ramsey is trying to burst and that fails. If you replace the first 4 MB bank with FP, burst mode will be disabled. (I'd be happy to swap 4 MB FP for SC... ;-)) It should even be possible to fiddle with Ramsey's registers and deactivate burst with a tiny tool. I wrote something like that (for the bus timeout option) wayyy back, dunno if I can still find it.

If you don't want to use any software method (requires a little something to be executed after boot), just pull one chip of the first bank and the rest will be ignored.

[Zac67]

Actually it's more a bug of the CPU card - they shouldn't try to initialize a burst transfer if they can't manage to do so.

Ramsey can only do '030 bursts which (I was told) are totally different from '040 bursts... Using a fast page ZIP in the first bank will disable burst mode completely and (if that is the cause) will solve the problem.

Followup: found some of my old notes - the Ramsey register in question is $DE0003:
Bit 0: page mode
Bit 1: burst mode
Bit 2: burst wrapping
Bit 3: RAM size (0=1M, 1=4M)
Bit 4: RAM width (0=1 bit, 1=4 bit) //whoah - never knew 1 bit was possible...
Bits 5-6: refresh rate
link

So all you have to do is to turn off bit 1 (you might have to be in supervisor mode to access Ramsey) and that'll disable burst mode with SC RAMs - voilá.  ;-)

[Zac67]

SC chips end in ..02, FP in ..00. If your first bank is SC and the rest mixed - well, that ain't good for stability...
A mixed setup in the first bank should disable burst mode, but I'm not sure what exact method the ROM uses for detection...

[Zac67]

There are couple of tools on Aminet that you should try first.