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ZXnet http server: QBus Cards: Emulex UC07/UC08 QBus SCSI Controller



DEC Systems

DEC hardware

Emulex UC07/UC08 QBus SCSI Controller

The Emulex UC07 and UC08 are SCSI Controllers for QBus systems supporting either MSCP or TMSCP. The UC07 can be configured to use either disks or tapes, but not at the same time. The UC08 has two SCSI busses allowing you to run both disks and tapes off the same card (disks on one SCSI port, tapes on the other). The UC07-III and UC08-III variants are designed for use with the MicroVAX III.

Subsystem Overview (from the Manual)

The UC07 Host Adapter connects high-capacity SCSI-compatible magnetic disk, optical disk, or magnetic tape subsystems to the Q-Bus in computers manufactured by Digital Equipment Corporation (DEC). Via switch selection, the UC07 implements either DEC's Mass Storage Control Protocol (MSCP) for disk subsystems or Tame Pass Storage Control Protocol (TMSCP) for tape subsystems to provide a software-transparent interface for the host DEC computer. The Small Computer Systems Interface (SCSI) peripheral interface provides traditional Emulex flexibility in peripheral selection.

The UC08 Host Adapter combines the capabilities of two UC07s on a single printed circuit board assembly. This allows the user to separate slow and fast SCSI peripherals, attaching slower tape devices or optical drives to one SCSI bus, while high-speed magnetic drives use the other SCSI bus.

Physical Organization Overview (from the Manual)

The UC07 or UC08 Intelligent Host Adapter is a quad-wide printed circuit board that contains either one (UC07) or two (UC08) microprocessor-based SCSI host adapters. The board connects directly to the host computer's Q-Bus.

In MSCP mode, each UC07 or UC08 SCSI port can support up to seven SCSI peripheral controllers. Each peripheral controller can have from one to eight devices attached to it. Regardless of the combination scheme, eight (8) is the maximum number of logical units that can be attached to a single UC07 or UC08 SCSI Port. The SCSI devices can be a mixture of magnetic disk or optical disk devices. Special software might be required when mixing optical and magnetic devices on the same UC07 or UC08.

In TMSCP mode, each UC07 or UC08 SCSI port can support up to seven tape devices with a SCSI interface.


The UC07/UC08-III appears to have non-standard SCSI ports. The SCSI ports on my UC08-III are the 50-pin HD ports just like one would find on SCSI-2 hardware. Only problem is the ports are the wrong gender - they are the same gender as typical SCSI-2 cables so none of them will plug into the controller. It is also possible that the pinout may be different but I have not done any tests to see. My controller came with two cables both ending in a centronics plug so its not too much of a problem.


Unlike the CMD CQD-220 SCSI controllers, the UC07/UC08 need to do their own low-level format on the drives and map geometries, etc. This means that to add a new disk, you have to go into its firmware. Getting into the firmware isnt terribly difficult and the controller even has a nice little menu system to make configuring the device fairly easy. When you remove a disk, the controller will still report it as being present (but offline) to any software.

Accessing the Firmware

To access the controllers firmware, you need to enter the following commands at the chevron prompt:

  >>> I
  >>> D/P/W 20001F40 20
  >>> D/P/L 20088000 80000000
  >>> D/P/L 20088004 80000001
  >>> D/P/W 2000XXXX 1
  >>> D/P/W 2000YYYY 3003
  >>> D/P/W 2000YYYY 4401
  >>> S 80

You should wait a few seconds before running the final command (S 80) - if this command fails, wait a bit longer. The XXXX and YYYY depend on the controllers address and can be found in the following table (any typos arent my fault - I copied them from somewhere else!):

  Address          XXXX       YYYY
  17772150         1468       146A
  17772154         146C       146E
  17760334         00DC       00DE
  17760340         00E0       00E2
  17760344         00E4       00E6
  17760350         00E8       00EA
  17760354         00EC       00EE
  17760360         00F0       00F2
  17760364         00F4       00F6
  17760370         00F8       00FA
  17760374         00FC       00FE
  17760400         0100       0102
  17760404         0104       0106
  17760410         0108       010A
  17760414         010C       010E
  17760420         0110       0112
Jumper Settings

The CSR value is set on switch packs labeled SW3 and/or SW4

|       |  SW3/4  |
|CSR    | 1 2 3 4 |
|72150  | 0 0 0 0 |
|72154  | 1 0 0 0 |
|60334  | 0 1 0 0 |
|60340  | 1 1 0 0 |
|60344  | 0 0 1 0 |
|60350  | 1 0 1 0 |
|and so on down to|
|60420  | 1 1 1 1 |

The following details some other jumpers and was stolen from

1	off- run 	on- reset/halt
2	off- enable  	on- disable
3 	reserved
4	off-normal 	on-loop self test

5	off-TMSCP 	on-MSCP
6	(mscp only) 	off-disable autoboot on-enable autoboot

interrupt request level (default is 4 and the manual highly recommends it)
quad wide uco7/8        4       5
scsi bus 1 - jumper PR	in	out
                    RS	out	in

bus 2-		    LM
		    MN same as above

on a dual-wide UC07, same story, but they're jumpers TU and UV

On my UC08 controller, the switches are set to 0100 which gives it the CSR address 60334. Looking 17760334 in the table gives XXXX = 00DC and YYYY = 00DE. This results in the following set of commands to execute at the chevron prompt:

  >>> I
  >>> D/P/W 20001F40 20
  >>> D/P/L 20088000 80000000
  >>> D/P/L 20088004 80000001
  >>> D/P/W 200000DC 1
  >>> D/P/W 200000DE 3003
  >>> D/P/W 200000DE 4401
  (wait a second)
  >>> S 80




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