From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Fuchs Subject: Re: Auto RS485 half-duplex control Date: Sun, 24 Jan 2010 17:06:36 +0100 Message-ID: <201001241706.37479.mfuchs@ma-fu.de> References: <001801ca8c76$d7654bd0$862fe370$@cx> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mo-p00-ob.rzone.de ([81.169.146.162]:58566 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753803Ab0AXQZi convert rfc822-to-8bit (ORCPT ); Sun, 24 Jan 2010 11:25:38 -0500 In-Reply-To: <001801ca8c76$d7654bd0$862fe370$@cx> Content-Disposition: inline Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Christian Magnusson Cc: linux-serial@vger.kernel.org Christian, >=20 > I have searched in the lists for some kernel support to control the R= TS-pin > while sending characters to through an external RS232->RS485 adapter. > The RS485 device I=92m writing to, respond with an answer within appr= oximately > 2ms after my last sent character, and therefore I need to release the > RTS-pin before that. > If not, the returning characters will be unreadable due to the > send-collision. >=20 > Will this feature be implemented in the i386 arch (as it is for chris= ), or > is there any reason to never include it in the future? >=20 manually controlling the RTS (or any other pin) pin for RS485 duplex control has been discussed here several time. Because it is not possibl= e to guarantee the correct timing in any situation this was always nack'd= =2E The only chance you have is to use a proper UART that is capable to do = this by hardware (e.g. some Exar UARTs or some UARTs that can be found on so= me SoCs that are used in the embedded world). Matthias -- To unsubscribe from this list: send the line "unsubscribe linux-serial"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html