17 Apr
2025
17 Apr
'25
3:12 p.m.
On Apr 17, 2025, at 7:36 AM, Jos Fries via cctalk
<cctalk(a)classiccmp.org> wrote:
Mattis Lind wrote:
Check the PDP-11 Architecture Handbook (1983-84) Appendix A — Assignment of Addresses and
Vectors, for DEC’s preferred addresses for devices. The default address for an RK11 is
777400 with an interrupt vector of 220. You can put it anywhere you want that doesn’t
conflict with another device, but the benefit of using the DEC default is that things like
bootstrap code and pre-built s/w images will find and use it at the default address.
—Milo
Most (All?) unibus devices can be set anywhere in
the PDP-11 IO space. This
means the last 8kbyte of the 256k Unibus space. Addresses 760000 - 777777
octal. A quick glance at the schematic shows that this is true for the
RK11-D as well. What is interesting though is that the doc mentions 8
address jumpers while according to the schematic it has 10. Jumpers W4-W13.
/Mattis
Aha, thanks, that explains the situation! I found the jumpers in the drawings and found
the address bits that can be configured.
Jos