30 Nov
2016
30 Nov
'16
4:22 a.m.
On 11/29/16 1:24 PM, Charles Dickman wrote:
On Tue, Nov 29, 2016 at 12:54 PM, Toby Thain <toby
at telegraphics.com.au> wrote:
The major advantage of using chipkit parts is space. If you build on a
quad wide board
then its fairly easy to do DMA, bus arbitration, interrupt chain, and
interrupt vectors
as its all documented in the various Qbus PDP-11 books.
About the only thing I've done is simple parallel interfaces as any
other function
was available built. Though one of these days a CF "disk" board with
boot rom
would be handy. that would make a 11/23, dlv11j, memory and self contained
disk card a nice 4 board system in a BA11-VA box.
Allison
On 2016-11-29 12:22 PM, Noel Chiappa wrote:
> > From: Peter Coghlan
>
> > Can anyone suggest an existing, simple QBUS device that I could
> study
> > the documentation of to figure out what a basic QBUS device needs to
> > have and to give me some ideas on how to implement one?
>
> Depends. Do you want to be able to do interrupts? Do you want to be able
> to
> do DMA? Each is a significant increment in complexity.
>
> Later DEC QBUS devices may not be the best things to look at, since they
> tend
> to use special DEC QBUS control chips (I'm _not_ talking about bus
> transceiver chips here) which are of course no longer available.
The DEC
Chipkit documentation has the internal schematics for the
standard DEC interface chips and is very much worth a read.