Newsgroups: comp.sys.transputer
From: teig@autro1.UUCP (Oyvind Teig)
Subject: occam CHAN vs. PORT
Organization: Autronica A/S, Trondheim, Norway
Date: 27 Oct 94 12:14:44 GMT
Message-ID: <189@autro1.UUCP>

OCCAM CHAN vs. PORT

Questions below concern memory mapped I/O only:
Q1.  CHAN and PORT - What is the difference?
Q2.  Which do I use if I want to access memory mapped I/O?
Q3.  Which do I use if I later on want to make a simulator for the I/O?
Q4.  How do I access memory mapped registers on a UART?

I think the answers are like this, please correct:
A1?  PORT/CHAN     OF BYTE
     PORT/CHAN     OF [16]BYTE
     [16]PORT/CHAN OF BYTE
     No PORT OF protocol
     Both may be PLACEd at a memory address
     PORT is bidirectional
A2?  CHAN OR PORT, either one
A3?  Not PORT because occonf gives a warning that a PORT should be PLACEd
A4?  CHAN/PORT     OF [16]BYTE   ??
     [16]CHAN/PORT OF BYTE       ??
     A PORT is bidirectional, ok, but not 'simulator-friendly'
     If I use CHAN, do I have to make one declaration for I and one for O?

Cheers, 0yvind Teig Autronica Norway 27.10.94

