9 Jan
2002
9 Jan
'02
9:19 a.m.
I think I finally get the picture on the addressing...However,
that raises two more questions. If my program is trying to talk to a
22-bit address, and I have 18-bit addressing, will it not work, or will it
be converted? Also, if my backplane becomes 22-bit (by replacing it or
adding the jumpers for the other 4 bits) does everything automagically
change to 22-bit, or do you change a jumper on the M8186, or on the MSV11,
or both?
Thanks,
Tom
On Wed, 9 Jan 2002, Pete Turnbull wrote:
Well, if you're using 18-bit addressing -- which
you must be if the DRV11-B
responds to 772410 rather than 17772410 -- then all the I/O addresses begin
77.... rather than 17.... 17.... in ODT would address the memory. I/O
addresses are often given as 17.... for older QBus devices, because the
original LSI/11 used 16-bit addressing. You have to mentally add two or
six more '1's on the front for an 11/23 or later processor.