From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4C0F327F.8020900@domain.hid> Date: Wed, 09 Jun 2010 08:19:43 +0200 From: Wolfgang Grandegger MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] RTDM rs232 strange behavior List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Everett Wang Cc: xenomai@xenomai.org On 06/05/2010 04:22 AM, Everett Wang wrote: > Hi All, > > I am playing around with xenomai and RTDM serial driver on a > 1.7Ghz Pentium-M machine running xenomai 2.5.3. The example cross-link > produced this result: > > main : starting read-task > Nr | write->irq | irq->read | write->read | > ----------------------------------------------------------- > 0 | 118948 | 614135 | 733083 > 1 | 115598 | 614281 | 729879 > 2 | 108917 | 614982 | 723899 > 3 | 106101 | 616560 | 722661 > 4 | 113457 | 614971 | 728428 > 5 | 110358 | 614265 | 724623 > 6 | 106499 | 614406 | 720905 > 7 | 110363 | 615015 | 725378 > 8 | 115478 | 614840 | 730318 > 9 | 110766 | 614168 | 724934 > 10 | 108986 | 616435 | 725421 > 11 | 108030 | 614299 | 722329 > 12 | 109369 | 614420 | 723789 > 13 | 105862 | 614456 | 720318 > 14 | 110428 | 616301 | 726729 > > Is 0.7 millisecond between write and read a reasonable number? I just ran this test on my PC and got similar results. The figures are in *nanoseconds*. And yes, stupid me, 0.7 *milli-seconds* is a resonable number for 115200: (2 * 4 bytes * 10 bits-per-byte) / 115200 bits/sec. Wolfgang.