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Old 29 January 2015, 21:23   #10
Toni Wilen
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 43
Posts: 20,635
Originally Posted by mark_k View Post
Apparently the SCSI device can DMA into the on-board SRAM, but transfers from that to Amiga memory are done manually (PIO or maybe just copying memory if it's mapped into Amiga address space).
Got it working, mostly. RAM is at board + 0x4xxx. Each read always gets next byte or word, there seems to be internal hardware address counter. I think this was done because WD SCSI chip is not designed for PIO data read/write (it would be really slow, would need multiple IO access to read or write single byte).

Driver also refused to boot PFS3 partition (all partitions appeared in early startup) and for some reason it executes WD reset command all the time when idle. Probably best to get non-beta ROM first.

Masoboshi: difficult to guess IO mappings because it has both IDE and SCSI parts. IDE only rom would help.

ICD AdSCSI 2000: Unemulated 5380 chip. (should not be that difficult to emulate now that low level scsi emulator exists, it is quite low level chip). Other older SCSI controllers also use 5380 (or 53c80)
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