Never Mind: MicroVAX 3 - test-drb@ccmp.vtda.org

6 Sep 1999

...
 ALSO,  I am about to try out (if I can get a degausser)
some TK50 tapes
in a TK70.  But I want to be able to have both the TK50 and a TK70
tape drive on line. 
You certainly can!

...
   I have done a SYSGEN and the MUX.SYS device driver
allows two devices, (MU0: and MU1:), but I don't have the dip switch
settings for alternate CSR values.  Can anyone help?    PLEASE? 
On both the TQK50 and TQK70, the CSR is set by jumpers, not by DIPswitches.
(the DIPswitches on a TK50 actually set the rev level reported by TMSCP
inquiry commands, which changed more often than the CSR's at one point!)
The default CSR is 774500.  The CSR must be a multiple of 4, so the low two
bits are always zero, and the CSR must be in the I/O page, so the high
5 bits are always on.  The in-between bits are set with the jumpers near
the edge connectors.  Seen with the edge connectors to the bottom, the
default looks like:

   XXXXXX   (jumper in for CSR's starting with 77, jumper out for 76)

   XXXXXX   \
	    |
   .    .   |-  a "4"
	    |
   .    .   /

   XXXXXX   \
	    |
   .    .   |-  a "5"
	    |
   XXXXXX   /

   .    .   \
	    |
   .    .   |- a "0"
	    |
   .    .   /

   .    .   jumper in if last digit is "4", out if a "0".

The "autoconfigure" CSR selection for a second TK50 in a system is 760404,
though of course this moves around if you've got other second controllers
in the systems, or a serial multiplexer, and of course RT-11 doesn't care
a damn bit about autoconfigure rules as you've got to manually configure
it anyway :-)

-- 
 Tim Shoppa                        Email: shoppa(a)trailing-edge.com
 Trailing Edge Technology          WWW:   http://www.trailing-edge.com/
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