From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756755AbYJHV6p (ORCPT ); Wed, 8 Oct 2008 17:58:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754608AbYJHV6h (ORCPT ); Wed, 8 Oct 2008 17:58:37 -0400 Received: from khc.piap.pl ([195.187.100.11]:32806 "EHLO khc.piap.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754551AbYJHV6g (ORCPT ); Wed, 8 Oct 2008 17:58:36 -0400 To: "Jon Smirl" Cc: "Bill Gatliff" , "ARM Linux Mailing List" , lkml Subject: Re: Toggling GPIO at 38Khz References: <9e4733910810072043m6c69f3bdv104bd32928fe64ae@mail.gmail.com> <48ECA101.8010604@billgatliff.com> <9e4733910810080606ne8bdbb8v81d42069c985ae98@mail.gmail.com> From: Krzysztof Halasa Date: Wed, 08 Oct 2008 23:58:34 +0200 In-Reply-To: <9e4733910810080606ne8bdbb8v81d42069c985ae98@mail.gmail.com> (Jon Smirl's message of "Wed\, 8 Oct 2008 09\:06\:30 -0400") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Jon Smirl" writes: > These are external boards people buy to use with MythTV. They are most > commonly used on the x86, but the NSLU2 has been modified to use them > too. > > The hardware can't be changed, people have bought thousands of these devices. > > Many people cut up a serial cable and solder it themselves... Sure but you only need to bit-bang at 36 or so kHz while transmitting, right? The receive side is a slow one as the receiver chip has an integrated "demodulator". If so then personally... I'd abandon the simple TX circuit, and use a hardware ~36 kHz oscillator, gated by the serial output signal. I don't think such transmitters are in thousands. Tens, maybe - the cost of replacing/modifying them all should be insignificant. I guess one could design and produce such a TXer in less than 20 minutes. -- Krzysztof Halasa