1README file for the Linux DTC3180/3280 scsi driver.
   2by Ray Van Tassle (  March 1996
   3Based on the generic & core NCR5380 code by Drew Eckhard
   5SCSI device driver for the DTC 3180/3280.
   6Data Technology Corp---a division of Qume.
   8The 3280 has a standard floppy interface.
  10The 3180 does not.  Otherwise, they are identical.
  12The DTC3x80 does not support DMA but it does have Pseudo-DMA which is
  13supported by the driver.
  15It's DTC406 scsi chip is supposedly compatible with the NCR 53C400.
  16It is memory mapped, uses an IRQ, but no dma or io-port.  There is
  17internal DMA, between SCSI bus and an on-chip 128-byte buffer.  Double
  18buffering is done automagically by the chip.  Data is transferred
  19between the on-chip buffer and CPU/RAM via memory moves.
  21The driver detects the possible memory addresses (jumper selectable):
  22        CC00, DC00, C800, and D800
  23The possible IRQ's (jumper selectable) are:
  24        IRQ 10, 11, 12, 15
  25Parity is supported by the chip, but not by this driver.
  26Information can be obtained from /proc/scsi/dtc3c80/N.
  28Note on interrupts:
  30The documentation says that it can be set to interrupt whenever the
  31on-chip buffer needs CPU attention.  I couldn't get this to work.  So
  32the driver polls for data-ready in the pseudo-DMA transfer routine.
  33The interrupt support routines in the NCR3280.c core modules handle
  34scsi disconnect/reconnect, and this (mostly) works.  However.....  I
  35have tested it with 4 totally different hard drives (both SCSI-1 and
  36SCSI-2), and one CDROM drive.  Interrupts works great for all but one
  37specific hard drive.  For this one, the driver will eventually hang in
  38the transfer state.  I have tested with: "dd bs=4k count=2k
  39of=/dev/null if=/dev/sdb".  It reads ok for a while, then hangs.
  40After beating my head against this for a couple of weeks, getting
  41nowhere, I give up.  So.....This driver does NOT use interrupts, even
  42if you have the card jumpered to an IRQ.  Probably nobody will ever