[U-Boot] Daughter card detection

[Jerry Van Baren <gvb.uboot@gmail.com>]

Hi Kapil,

On 04/11/2011 12:06 AM, Dev, Kapil wrote:
> Hi I am trying to detect a daughter card chip. From data sheet I was
> able to find the address for that chip. But when I use i2c probe
> command from uboot shell, it is showing me only 4 addresses. And
> these 4 addresses does not contain the address of any chip on the
> daughter card.
> So my query is :
>
> 1.  how can I detect the daughter card chips using i2c.

The i2c probe command should work if your daughter card is working properly.

> 2.  why i2c probe command is not showing the chip addresses for
> daughter card as mentioned on the data sheet. But that is giving the
> correct address of EEPROM.

What is the target chip that is not responding?  You have given us no 
useful information.

I would connect a logic analyzer (preferred) or scope to the SDA and SCL 
lines on the I2C chip on your daughter card and verify the signals are 
making it to the chip and are valid signals.  It is tough with a scope, 
but with a logic analyzer you should be able to decode the signals and 
see the target chip's response or lack thereof.

> Here I want to mention that the card is working fine but not able to
> identify the chips on the daughter card mounted on davinci evm
> board.

Best regards,
gvb