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.
15Its 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

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