From: Timur Tabi <timur@freescale.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] MPC8572E I2C bus speed after emulator reset
Date: Fri, 27 Mar 2009 13:23:58 -0500 [thread overview]
Message-ID: <49CD19BE.1080904@freescale.com> (raw)
In-Reply-To: <43EB80E07C42E1408726E4905FB96B04C08045@CYBORG3.cyclone.com>
Scott Coulter wrote:
> Hi Timur,
>
>> What is the value of CONFIG_SYS_I2C_SPEED in your board header file?
>
> #define CONFIG_SYS_I2C_SPEED 400000
So far, so good.
>> What values does function set_i2c_bus_speed() in fsl_i2c.c program
>> into the FDR and DFSR registers?
>
> According to my printfs and the emulator readback of the values, the
> code is putting a 0x6 into the FDR and a 0x1 into the DFSR. These
> values appear to be identical with either a hard reset or an emulator
> reset.
According to the 8572E RM, the default values for DFSR and FDR are 0x10
and 0x00. The values above represent, according to the table, a divider
of 768. The RM also says that I2C clock is 1/2 CCB, so that means that
your CCB should be 400,000 * 768 * 2 = 614MHz. Is that right?
--
Timur Tabi
Linux kernel developer at Freescale
prev parent reply other threads:[~2009-03-27 18:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-27 16:52 [U-Boot] MPC8572E I2C bus speed after emulator reset Scott Coulter
2009-03-27 17:57 ` Timur Tabi
2009-03-27 18:05 ` Scott Coulter
2009-03-27 18:23 ` Timur Tabi [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=49CD19BE.1080904@freescale.com \
--to=timur@freescale.com \
--cc=u-boot@lists.denx.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.