> On Apr 17, 2025, at 7:36 AM, Jos Fries via cctalk <[email protected]>
> wrote:
>
> Mattis Lind wrote:
>> 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
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
