From: bgat@billgatliff.com (Bill Gatliff)
To: linux-arm-kernel@lists.infradead.org
Subject: Generic GPIO I2C bitbang kernel question
Date: Fri, 02 Oct 2009 13:26:53 -0500 [thread overview]
Message-ID: <4AC645ED.3080904@billgatliff.com> (raw)
In-Reply-To: <3d1967ab0910021119g5d81e8dar1056ef37ca8d4e35@mail.gmail.com>
Brian Hutchinson wrote:
>
> Good talking to you again at ESC!
Likewise! When are you going to give an actual presentation? :)
> I've sense been able to get the i2c-core bit banging to work! I wrote
> a user land app to write to a eepot and it is working now. The
> problem was in fact the line I mentioned that was driving SDA high
> when it should have been turned into a input to look for the ACK from
> the slave.
Aaah. With I2C, you never "drive" the line high--- that's what the
pullups are for.
So if you want to output a zero, you drive the line low. To output a
one, you float the line.
b.g.
--
Bill Gatliff
bgat at billgatliff.com
prev parent reply other threads:[~2009-10-02 18:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-01 2:17 Generic GPIO I2C bitbang kernel question Brian Hutchinson
2009-10-02 15:31 ` Bill Gatliff
[not found] ` <3d1967ab0910021119g5d81e8dar1056ef37ca8d4e35@mail.gmail.com>
2009-10-02 18:26 ` Bill Gatliff [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4AC645ED.3080904@billgatliff.com \
--to=bgat@billgatliff.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).