🚀 go-pugleaf

Thanks for all your help on the buffers for the transputer link.   Now
I have an extremely technical query about the C011 adaptor itself.
What I am trying to do is use the input of the C011 to read in the
data on the link, but leave the output disconnected so that
acknowledges are not transmitted.   The acknowledges are to be handled
by the normal transputer at the other end of the link.   A diagram is
shown below:-

________                         ________
Transp.|                         |Transp.
  1    |-----<-----<-----<-----<-|  2
       |        Tap              |
l.out  |----->---o->----->----->-| l. in
_______|         |               |_______
                 |           _____________
                 |----->---->|C011 input |-----\
                             |           |      \ parallel bus to
              N/C <-----<----|C011 output|      / processor
                             |___________|-----/

The problem that I have is that the data sheets do not indicate
whether this type of operation is possible.   The data book gives the
timings in the following form:-
       ______________________________________________________________
LinkIn      Data (11 bits)|____________________|Data (11 bits)
       _____________________ ________________________________________
Q0-7   _____________________X________________________________________
                                _________
QValid ________________________/         \___________________________
                                  __________
QAck   __________________________/          \________________________
       ______________________________________________________________
LinkOut_________________________________|Ack|________________________

What the data-book doesn't tell me is if the C011 can be used as shown
below so that overlapping ACK implemented on Transputer 2 will still
work.   The resultant waveform would have to look like this:-
       ______________________________________________________________
LinkIn      Data (11 bits)|        Data (11 bits)       |Data (11 bits)
       _____________________ _____________________________ __________
Q0-7   _____________________X_____________________________X__________
                                _________                     _______
QValid ________________________/         \___________________/
                                  __________                    _____
QAck   __________________________/          \__________________/
       ______________________________________________________________
LinkOut_________________________________|Ack|________________________

The LinkOut of the C011 is not connected, so the last waveform on this
diagram is irrelevant, but is included for completeness.   As can be
seen, the data is arriving at the LinkIn input before the C011 has had
time to signal that the previous byte has arrived, and set up all of
its Q0-7, QValid, and QAck signals.   I know that this is a rather
unorthodox way of doing things, but I can see no other way around it.
Also does anyone have an idea what an Ack arriving at LinkIn when no
data has been sent down LinkOut will do?

If anyone has any ideas could you mail them to me, and I'll produce a
summary in about a weeks time (or maybe longer depending upon the
response).

Thanks (in anticipation),
Dave.


    David I. Laurenson                |
    Department of Computer Science    |
    Edinburgh University King's Bldgs |  JANET   dil@uk.ac.ed.lfcs
    Mayfield Road, EDINBURGH  U.K.    |