English Amiga Board - View Single Post - Blizzard 1230 + PFS-AIO Unexpected Phase Change

Toni Wilen · 30 January 2018, 20:24

Thanks. I had to duplicate it myself because it wasn't trivial issue. (and unexpectedly I managed to duplicate it instantly and reliably! Thats rare..)

Fixed. This write operation wrote two bytes to SCSI chip's FIFO and then started DMA (with size - 2 of total transfer size). Data in FIFO was ignored which caused phase mismatch.

I am not sure why SCSI Kit does this, possibly DMA requires long word alignment? But on the other hand DMA IO address and length is in words, not in longs.

30 January 2018, 20:24	#4
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,502	Thanks. I had to duplicate it myself because it wasn't trivial issue. (and unexpectedly I managed to duplicate it instantly and reliably! Thats rare..) Fixed. This write operation wrote two bytes to SCSI chip's FIFO and then started DMA (with size - 2 of total transfer size). Data in FIFO was ignored which caused phase mismatch. I am not sure why SCSI Kit does this, possibly DMA requires long word alignment? But on the other hand DMA IO address and length is in words, not in longs.