Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!snorkelwacker!bloom-beacon!eru!luth!sunic!mcsun!ukc!edcastle!lfcs!dil From: dil@lfcs.ed.ac.uk (David Laurenson) Newsgroups: comp.sys.transputer Subject: Transputer Link Analyser (C011) Message-ID: <1150@castle.ed.ac.uk> Date: 21 Nov 89 16:41:04 GMT Reply-To: dil@lfcs.ed.ac.uk (David Laurenson) Organization: Laboratory for the Foundations of Computer Science, Edinburgh U Lines: 69 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. |