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 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,3025dd6d917b499c X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.224.223.84 with SMTP id ij20mr1040352qab.5.1349974534631; Thu, 11 Oct 2012 09:55:34 -0700 (PDT) Received: by 10.236.88.236 with SMTP id a72mr269749yhf.20.1349974534595; Thu, 11 Oct 2012 09:55:34 -0700 (PDT) Path: r17ni19491880qap.0!nntp.google.com!l8no44909614qao.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Thu, 11 Oct 2012 09:55:34 -0700 (PDT) In-Reply-To: <1gvlt0jlx1mcm$.1qpdr3pr4aime.dlg@40tude.net> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=12.35.64.226; posting-account=qZVz2QoAAAAN9WxYp-9jYb7jORc4Zqwt NNTP-Posting-Host: 12.35.64.226 References: <38af7fb8-b0a4-4a31-87aa-b7b698cc89c3@googlegroups.com> <3ca0ffd0-1764-484b-8fab-17c0d2dd9463@googlegroups.com> <1f645050-cf4c-40bf-a797-9687b69e4a54@googlegroups.com> <18ats2960nsvm$.kfufsnul13aq$.dlg@40tude.net> <5072c9ae$0$6562$9b4e6d93@newsspool4.arcor-online.net> <4keoa6epdxt7.1nnwxy7v7ar90.dlg@40tude.net> <5072dc68$0$6554$9b4e6d93@newsspool4.arcor-online.net> <1f7cmfp1l65w1.1deog8cfxbs0u$.dlg@40tude.net> <5072e37a$0$6556$9b4e6d93@newsspool4.arcor-online.net> <1df8bb52-e659-4539-98f8-67ee60fbce1c@googlegroups.com> <1gvlt0jlx1mcm$.1qpdr3pr4aime.dlg@40tude.net> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Ada, the best language with the not-so-best tool chain From: mjsilva@scriptoriumdesigns.com Cc: mailbox@dmitry-kazakov.de Injection-Date: Thu, 11 Oct 2012 16:55:34 +0000 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Date: 2012-10-11T09:55:34-07:00 List-Id: On Thursday, October 11, 2012 9:20:25 AM UTC-7, Dmitry A. Kazakov wrote: > On Thu, 11 Oct 2012 08:44:39 -0700 (PDT), mjsilva@scriptoriumdesigns.com >=20 > wrote: >=20 >=20 > > I've got one AVR project with interrupts every 60us, and I need <1us >=20 > > latency.=20 >=20 >=20 >=20 > Like I said, mechanical processes are slow. And, anyway, there is no >=20 > affordable AD-DC converters to deliver 1us forward and backward conversio= n >=20 > time combined. I didn't say anything about ADC/DAC (though in fact the application is driv= ing 18 software PWM channels, so it is an analog application). > > The entire board is about 8 sq. cm. Should I port that over to >=20 > > Linux with 1000x the memory requirements, and if so, could I even get t= hat >=20 > > kind of response? >=20 >=20 >=20 > Controlling mechanical processes do not need such responses. I cannot >=20 > answer your question without knowing what are you going to achieve. One typical analog process that even an 8-bit device can control is brushle= ss DC motor control. AVRs are used in this all the time, and certainly any= low-end ARM can do it. These motors can run up to 50000 RPM, with control= loops running at 1ms and control functions running every 40us (Atmel AVR49= 2). >=20 > >> And who is talking about performance while choosing an ARM? >=20 > >>=20 >=20 > >>> GNAT is running on ARM under RTEMS. I don't know what the current bar= e >=20 > >>> metal status is for ARM, although people have posted in the past in >=20 > >>> c.l.a about work they have done on this. >=20 > >=20 >=20 > > RTEMS takes on the order of 1MB of memory, I believe. Way too big for = a >=20 > > great many otherwise useful 32-bit parts. >=20 >=20 >=20 > How could 1MB be too big for 32-bit address space? >=20 >=20 >=20 > In any case, memory footprint is my least concern when designing an >=20 > embedded application. These 32-bit ARM parts can have as little as 8k of flash, and they range up= from there to perhaps 1MB onboard for the largest of the lower-end parts. = So the vast majority of them could not run an RTEMS-based Ada application.