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From: Phil <phil-FnsA7b+Nu9XbIbC87yuRow@public.gmane.org>
To: Stefan Wahren <info-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
Cc: linux-rpi-kernel
	<linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: i2c-bcm2835: Unable to read from i2c0
Date: Thu, 28 Jan 2016 22:49:56 +0000	[thread overview]
Message-ID: <7de3fd0b-7973-476c-a009-e9a1fb032a80@email.android.com> (raw)
In-Reply-To: <56AA8B75.9060801-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>

A few questions:

1) What has changed in your system? Have you ever been able to use the PiGlow?

2) What is the state of the GPIOs?

Phil

On 28 Jan 2016 9:43 p.m., Stefan Wahren <info@lategoodbye.de> wrote:
>
> Hi, 
>
> i'm using a Raspberry Pi B (rev 1) and Linux kernel 4.5rc-1. I have 
> connected a PiGlow (SN3218 at address 0x54) to the P1 Header. The I2C 
> bus clock is set to 100 kHz.  Every time i want to read data from i2c0 
> the following error appear: 
>
> [   94.343612] i2c-bcm2835 20205000.i2c: i2c transfer failed: 100 
>
> According to the BCM2835 datasheet this should be an ERR ACK (Slave has 
> not acknowledged its address). 
>
> > i2cdetect -y 0 
> 0 1 2 3 4 5 6 7 8 9 a b c d e f 
> 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 70: -- -- -- -- -- -- -- -- 
>
> > i2cdetect -q -y 0 
>       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f 
> 00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 50: -- -- -- -- 54 -- -- -- -- -- -- -- -- -- -- -- 
> 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
> 70: -- -- -- -- -- -- -- -- 
>
> Strangly writing data to the SN3218 works. 
>
> Does anyone have an explanation for this error? 
>
> Regards 
> Stefan 
>
> _______________________________________________ 
> linux-rpi-kernel mailing list 
> linux-rpi-kernel@lists.infradead.org 
> http://lists.infradead.org/mailman/listinfo/linux-rpi-kernel 
_______________________________________________
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  parent reply	other threads:[~2016-01-28 22:49 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-28 21:43 i2c-bcm2835: Unable to read from i2c0 Stefan Wahren
     [not found] ` <56AA8B75.9060801-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2016-01-28 22:49   ` Phil [this message]
     [not found]     ` <7de3fd0b-7973-476c-a009-e9a1fb032a80-2ueSQiBKiTY7tOexoI0I+QC/G2K4zDHf@public.gmane.org>
2016-01-29 18:16       ` Stefan Wahren
     [not found]         ` <56ABAC83.4000402-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2016-01-29 18:47           ` Phil

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