[U-Boot-Users] PQ2FADS i2c -- no SCL

[U-Boot-Users] PQ2FADS i2c -- no SCL

[Scott McNutt]

Using u-boot 1.0.1 with PQ2FADS ... we're
not seeing SCL while executing i2c commands.
Port D settings are correct, copper is good.

Has anyone seen a similar problem? Anyone
successful?

Regards,
--Scott

[U-Boot-Users] PQ2FADS i2c -- no SCL

[Yuli Barcohen]

>>>>> Scott McNutt writes:

    Scott> Using u-boot 1.0.1 with PQ2FADS ... we're not seeing SCL
    Scott> while executing i2c commands.  Port D settings are correct,
    Scott> copper is good.

    Scott> Has anyone seen a similar problem? Anyone successful?

It used to work on MPC8260ADS and MPC8266ADS. On PQ2FADS, I2C is
connected to nothing so it was not tested. It's expected to be the same
as on older boards. I assume you use the expansion connector to add I2C
hardware.  I'd check first of all that the configuration (S/W and H/W)
is the same as on older boards. Specifically, your add-on H/W must take
care of I2C bus requirements.

-- 
========================================================================
 Yuli Barcohen       | Phone +972-9-765-1788 |  Software Project Leader
 yuli at arabellasw.com | Fax   +972-9-765-7494 | Arabella Software, Israel
========================================================================

[U-Boot-Users] PQ2FADS i2c -- no SCL

[Herb Radford]

I've done a recent port of U-Boot 1.0.0 to our MPC866 card and found a 
change was necessary for I2C to do anything (could not get output on SCL or 
SDA).
In the init code for I2c there was a statement which cleared rpbase to 0. 
The docs for the 866 indicate not to change this field!
I commented it out just on a hunch and I2C works!
Try that, maybe it'll help you.

Regards, Herb

At 04:01 AM 1/21/2004, you wrote:

> >>>>> Scott McNutt writes:
>
>     Scott> Using u-boot 1.0.1 with PQ2FADS ... we're not seeing SCL
>     Scott> while executing i2c commands.  Port D settings are correct,
>     Scott> copper is good.
>
>     Scott> Has anyone seen a similar problem? Anyone successful?
>
>It used to work on MPC8260ADS and MPC8266ADS. On PQ2FADS, I2C is
>connected to nothing so it was not tested. It's expected to be the same
>as on older boards. I assume you use the expansion connector to add I2C
>hardware.  I'd check first of all that the configuration (S/W and H/W)
>is the same as on older boards. Specifically, your add-on H/W must take
>care of I2C bus requirements.
>
>--
>========================================================================
>  Yuli Barcohen       | Phone +972-9-765-1788 |  Software Project Leader
>  yuli at arabellasw.com | Fax   +972-9-765-7494 | Arabella Software, Israel
>========================================================================
>
>
>
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[U-Boot-Users] PQ2FADS i2c -- no SCL

[Scott McNutt]

>
>     Scott> Using u-boot 1.0.1 with PQ2FADS ... we're not seeing SCL
>     Scott> while executing i2c commands.  Port D settings are correct,
>     Scott> copper is good.
> 
>     Scott> Has anyone seen a similar problem? Anyone successful?
> 
> It used to work on MPC8260ADS and MPC8266ADS. On PQ2FADS, I2C is
> connected to nothing so it was not tested. It's expected to 
> be the same as on older boards.

I agree :-)

> I assume you use the expansion connector to add I2C
> hardware.

Correct.

> I'd check first of all that the configuration
> (S/W and H/W)is the same as on older boards. Specifically,
> your add-on H/W must take care of I2C bus requirements.

SDA and SCL are pulled up as required. We got it working
by disabling open-drain output for SCL (PD14 ODR = 0).
Perhaps the transceiver (U18) has gone soft on us.

So ... this work-around is ok only for single master.

Yuli, if you ever get around to trying this on your
board, I'd be interested to know if you observe the
same behavior. Perhaps just scope SCL with a pull up
without a slave device.

Thanks for your suggestions.

Regards,
--Scott