From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.182.87.225 with SMTP id bb1mr5753177obb.16.1391773455234; Fri, 07 Feb 2014 03:44:15 -0800 (PST) X-Received: by 10.140.94.11 with SMTP id f11mr296746qge.7.1391773455195; Fri, 07 Feb 2014 03:44:15 -0800 (PST) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!peer02.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!c10no11563787igq.0!news-out.google.com!s3ni9959qas.0!nntp.google.com!f11no13387495qae.1!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Fri, 7 Feb 2014 03:44:15 -0800 (PST) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=189.77.226.1; posting-account=TRgI1QoAAABSsYi-ox3Pi6N-JEKKU0cu NNTP-Posting-Host: 189.77.226.1 References: <5e8fad3a-94e6-4517-af54-db8b4146803e@googlegroups.com> <858uto3cj3.fsf@stephe-leake.org> <1lg4oeejbp1e5$.h5mrspzez74h$.dlg@40tude.net> <05af11ec-d8bf-49e0-9d16-67afbba7423e@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Raspberry Pi, Real-Time and Ada From: "Rego, P." Injection-Date: Fri, 07 Feb 2014 11:44:15 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Received-Bytes: 2402 X-Received-Body-CRC: 403808845 Xref: news.eternal-september.org comp.lang.ada:18421 Date: 2014-02-07T03:44:15-08:00 List-Id: > I went back and had a closer look at this. (I've never actually used > Linux to drive GPIO lines as I either use a dedicated RTOS or just > write the code for bare metal mode). > It appears there are two ways of accessing the GPIO lines on the > Raspberry Pi under Linux: either via the /sys/class/gpio interface > or directly via memory mapped I/O. > It looks like all the types of performance comments I remember come > from the first access method and that you can get far better access > times using the second method. > Which method are you using ? At this time in RPi, none of them. For now I am still studying the board be= fore coding, as I should port an application to it in the next days. But I = am still evaluating if the RPi serves to my app. Timing constraints are the= top concern. But there as others, for example I just have 1 PWM exposed in= RPi and I would need at least 4; this is a minor concern if I can control = some GPIOs using timers, or use an external board to do it for me, but it w= ould be better if I had more PWM. Rego.