From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Edwards Subject: Re: [PATCH] Documentation about RS485 serial communications Date: Tue, 19 Oct 2010 14:29:48 +0000 (UTC) Message-ID: References: <20100408111310.524f7354@lxorguk.ukuu.org.uk> <4BBDD71D.1010700@evidence.eu.com> <4BFD1FB6.8050405@atmel.com> <4BFE2F38.8050200@evidence.eu.com> <4BFE41FD.2080804@atmel.com> <20100527102917.GB31253@pengutronix.de> <4C626CBF.9020609@evidence.eu.com> <20100811083214.21d2919e.randy.dunlap@oracle.com> <4C669120.8080707@evidence.eu.com> <4C686411.3060500@oracle.com> <20100815221906.GA24153@n2100.arm.linux.org.uk> <4CBD8EE4.5040808@evidence.eu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from lo.gmane.org ([80.91.229.12]:46136 "EHLO lo.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752172Ab0JSO36 (ORCPT ); Tue, 19 Oct 2010 10:29:58 -0400 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1P8DCP-0002cy-W1 for linux-serial@vger.kernel.org; Tue, 19 Oct 2010 16:29:57 +0200 Received: from dsl.comtrol.com ([64.122.56.22]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 19 Oct 2010 16:29:57 +0200 Received: from grant.b.edwards by dsl.comtrol.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 19 Oct 2010 16:29:57 +0200 Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org On 2010-10-19, Claudio Scordino wrote: > +2. HARDWARE-RELATED CONSIDERATIONS > + > + Some CPUs (e.g., Atmel AT91) contain a transceiver capable of working both > + as RS232 and RS485. Pardon my curiosity, but I've looked at a few AT91 parts, and I've never seen on with an internal transceiver -- nor does Google seem able to find any. Frankly, I'd be pretty surprised, since it would be very difficult (fab-wise), to build a mircoprocessor with I/O cells capable of withstanding the voltage levels specified in RS232. Can you specify to which parts you're referring? -- Grant Edwards grant.b.edwards Yow! I have the power to at HALT PRODUCTION on all gmail.com TEENAGE SEX COMEDIES!!