From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32328 invoked by alias); 11 Sep 2003 06:04:34 -0000 Mailing-List: contact ecos-discuss-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: ecos-discuss-owner@sources.redhat.com Received: (qmail 32311 invoked from network); 11 Sep 2003 06:04:33 -0000 Received: from unknown (HELO mailserver.pop-siegen.de) (62.157.218.43) by sources.redhat.com with SMTP; 11 Sep 2003 06:04:33 -0000 Received: (qmail 7836 invoked from network); 11 Sep 2003 06:04:32 -0000 Received: from unknown (HELO 192.168.150.70) (62.157.218.206) by dns.pop-siegen.de with SMTP; 11 Sep 2003 06:04:32 -0000 To: ecos-discuss@sources.redhat.com From: eibach@gdsys.de Date: Thu, 11 Sep 2003 13:37:00 -0000 Priority: normal X-Priority: 3 (Normal) Importance: normal X-David-Sym: 0 X-David-Flags: 33554432 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7Bit Subject: [ECOS] Timing considerations X-SW-Source: 2003-09/txt/msg00197.txt.bz2 Hello, one of the things my eCos application has to do is to serve a serial port. Platform is an Atmel EB40A. The device connected to the serial port needs answers to its requests within 1 ms to work properly. My idea was the following: - use the EB40A hardware driver for the serial port - poll the driver every 1 ms using the cyg_io_read command (non-blocking) - polling could be triggered by an alarm - that would require a clock with a timing faster than 10 ms between ticks (which is the standard) - so i use CYGNUM_KERNEL_COUNTERS_CLOCK_OVERRIDE_... options to set the ticks to 100 us - then i can trigger the alarm every 10 ticks Am I on the right way? Has anybody better ideas? Could changing the time between ticks cause any problems? Regards, Dirk Eibach -- Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos and search the list archive: http://sources.redhat.com/ml/ecos-discuss