KDF 8189 processor board foobared (ebay warning)

[allison]

On 05/21/2017 11:51 AM, Rob Doyle via cctalk wrote:
> On 5/20/2017 7:01 AM, allison via cctalk wrote:
>> Best chip for hacking and useful off a board (Falcon, KXT11, RQDX,
>> others) is the T11.  Its easily > useful like a 8085 or Z80.
>
> How 'bout a brand new J11-based board for oldie S-100 systems?
>
> <http://www.s100computers.com/My%20System%20Pages/PDP11%20Board/PDP11%20Board.htm>
>
>
> Rob.
Rob,

A T-11 was easier and fewer issues.

The biggest issue with T/F/J-11 is that all IO is RBW (read before
write, even if read is not used)
making IO difficult.  This is solved by DEC by reading one address and
writing another.  For S100
 doing IO you create BBS7 (bank select 7, logical or of high order 3
bits) as IO/ROM space
and munge the IO address for read and write to be offset for a given target.

Allison