From owner-freebsd-arm@freebsd.org Fri Apr 19 15:59:27 2019 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 9D0A31570A70 for ; Fri, 19 Apr 2019 15:59:27 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 2930C85419 for ; Fri, 19 Apr 2019 15:59:27 +0000 (UTC) (envelope-from ian@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id D88BB1570A6F; Fri, 19 Apr 2019 15:59:26 +0000 (UTC) Delivered-To: arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B1F241570A6D for ; Fri, 19 Apr 2019 15:59:26 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from outbound3d.ore.mailhop.org (outbound3d.ore.mailhop.org [54.186.57.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 23BB285418 for ; Fri, 19 Apr 2019 15:59:26 +0000 (UTC) (envelope-from ian@freebsd.org) ARC-Seal: i=1; a=rsa-sha256; t=1555689560; cv=none; d=outbound.mailhop.org; s=arc-outbound20181012; b=lRm3jf7aREo2ClZb6DKO/0dfXkEGCAbSVwJGG8+RXq0IWktGlvrzn8N7vANBm9ExAdGteg6hXv389 ZgVWu9StDNcU2HHIU35JFMezuRekHfPYMHJrqp5bXe23oDMe8BhkJ1HJ0lLN3cGARzdELZoanaEM9a eI6AGpiOioGcN3h+pXaL/5C7qAPmiogpL4ndbBDbrufVhLJLdJqAi1huSZVUnXbkyFa0DecKZKJwG0 rxc9LN4/DltwRxhazTHMfiZdLr2T21WI4ls+5iaoRTmYg6FT0dptqMl40Qm0g1umFD1/+Kr5ugKrPN 3qWOxdZiaWjA+lSFq8yO0FJbIvQuXdw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=arc-outbound20181012; h=content-transfer-encoding:mime-version:content-type:references:in-reply-to: date:cc:to:from:subject:message-id:dkim-signature:from; bh=NMYGa0tBZiXoKl8+a2aasaSbUJRuZvIt9elfYg28A00=; b=MOBqKnOWEn6CAEdXi869Q7B/sGvWVutobWCHdfIhu5E0+InIiOOQAoKtYbyqd9wn9R6DfPbh+8vEL 7d/4ej7H3olrIrVnvdgKLa14o0bGzvFPboVfcg5YO12yT/8hXJtD1NYZyNoqJ9JysyvVMlH7f7kD7o pLlR2W644ilNgLfIHBLpTfXybr90wQCicEdCczXj6jcOPOV+YEuxk8R/vERurLnlo6iqP4x6+9oLYB QvG+9VIbWEZg4IewVaP2J2PPlqaJBJMIIUwBghqkewXT3/eV4b089aHbfaIPzlBsORnyySv/Gnjfmo jbfMZoKTKKbWYQBhAqm2KR1EnM8giGw== ARC-Authentication-Results: i=1; outbound3.ore.mailhop.org; spf=softfail smtp.mailfrom=freebsd.org smtp.remote-ip=67.177.211.60; dmarc=none header.from=freebsd.org; arc=none header.oldest-pass=0; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=dkim-high; h=content-transfer-encoding:mime-version:content-type:references:in-reply-to: date:cc:to:from:subject:message-id:from; bh=NMYGa0tBZiXoKl8+a2aasaSbUJRuZvIt9elfYg28A00=; b=qMZqC9ijd7tnJzA3/e8svGxB8XK9sGLr4swl8HQA9yTnoiCsRpebPP5HXApcYpPOlFmbaEpHuvxPo DQpuWonAECIa6KRtmYQHaGVu1cLdGziQVaXeItM7t5uSw+D9mNpMRYDWaPb+F+T780pRt3lhlvUKha gt31cuIQJ0aC+cVYIG8sBpDx51ri1qou/yrw2RMB5Ah2TbCeQ/bLv4MfHsSjQtfr+TN4y1LWnkt3DN ioYQeLG0PIp6jRZ+JjPJOHakmR6E3rlixn9n57noJdOX83eJ6OZng1jFr30nO9l8fxuWa1GzBaqWlc sVG2JVV6bX8hnehOam3pZBkau2uV25A== X-MHO-RoutePath: aGlwcGll X-MHO-User: 1465c33d-62bc-11e9-990e-673a89bc4518 X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 67.177.211.60 X-Mail-Handler: DuoCircle Outbound SMTP Received: from ilsoft.org (unknown [67.177.211.60]) by outbound3.ore.mailhop.org (Halon) with ESMTPSA id 1465c33d-62bc-11e9-990e-673a89bc4518; Fri, 19 Apr 2019 15:59:18 +0000 (UTC) Received: from rev (rev [172.22.42.240]) by ilsoft.org (8.15.2/8.15.2) with ESMTP id x3JFxEUD054239; Fri, 19 Apr 2019 09:59:14 -0600 (MDT) (envelope-from ian@freebsd.org) Message-ID: Subject: Re: i2c almost working for me, was Re: i2c still not working for me From: Ian Lepore To: Daniel Braniss Cc: "freebsd-arm@freebsd.org" Date: Fri, 19 Apr 2019 09:59:14 -0600 In-Reply-To: References: <12F641C3-9FAA-4A3A-BA18-A7302F3A0F5E@cs.huji.ac.il> <20190409095819.c560dbc156c46e5ca0244e3e@bidouilliste.com> <23A47048-642A-481C-B7BE-B61E55F82955@cs.huji.ac.il> <20190409171604.GA4581@bluezbox.com> <6119CE3B-6042-4DDC-82BE-B0C0C7ADA838@cs.huji.ac.il> <5D4799BC-08DF-4F3D-81A4-C2D938F4AF93@cs.huji.ac.il> <20190417222601.c037efe0cb48987c81032bac@bidouilliste.com> <64b5598e2c8c7265f89a31b1f191cb1be318788a.camel@freebsd.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 FreeBSD GNOME Team Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 23BB285418 X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-6.98 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; NEURAL_HAM_SHORT(-0.98)[-0.979,0]; REPLY(-4.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000,0] X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Apr 2019 15:59:27 -0000 On Fri, 2019-04-19 at 10:20 +0300, Daniel Braniss wrote: > > > > You can often compensate for a too-long cable by adding some stronger > > pullups. It's typical for a SOM to have pullups in the 4.7K range on > > i2c. You can add your own 1K pullups to see if that helps the rise > > times on the bus. > > well, at the moment it works ok with a 6m cable, i’ll try your suggestion soon. Wow, I'm surprised that works; when you said "long" I was thinking something like 1m. You might need some sort of active helper device, something like a TI txs0104e that has rise-time accellerators built in. Or, maybe you could just slow the bus down enough to allow for the rise/fall times on that big a capacitive load, like run the bus at 10 or 20khz instead of 100. -- Ian