[U-Boot-Users] Newbie questions

David Hawkins dwh at ovro.caltech.edu
Thu Sep 14 23:17:49 CEST 2006


Hi Bruce

I can't answer all your questions as I too am fairly new to this,
but ...

> 1) Will u-boot support a compact flash device on the local bus of an 
> MPC8347 (we would like to get u-boot from a small I2C EEPROM and 
> everything else including the kernel from a large compact flash device)?

Assuming the MPC8347 is much the same as the MPC8349E/EA, I doubt
that you can use U-Boot on I2C EEPROM. The boot process of the
MPC8349E is basically; read reset configuration words source
(pin strapping), read reset configuration words (from local
bus Flash or I2C EEPROM), boot to reset vector. The reset
vector is typically an 8MB memory window on the local bus,
where Flash is usually sitting with U-Boot loaded.

So 'we would like to get u-boot from a small I2C EEPROM' doesn't
seem like a feasible requirement. Of course if you have a
development board that does it this way, I'm happy to be
corrected.

> 2) Is it possible to connect to u-boot's "console" from an enet port or 
> can it only be accessed from a serial port?  If it can, I presume it can 
> then be used to load new versions of u-boot just like the serial port? 
>  (The reason for this is there may not be a serial port available in the 
> final design for the customer to use for field upgrades and we're 
> concerned about being able to upgrade u-boot if we need to ship a fix 
> for it in the future.)

I can't answer the console over ethernet question.

However, I would always try to make the serial port available on
the final design. Eg. take a look in the BDI2000 manual if you
have one, they define a couple of pins on the COP header
for use as a logic level RS232 interface.

You can always hide that serial port inside the box.

Consumer electronics such as the Linksys NSLU2 and WRT54G do
things this way, i.e., logic level serial port and JTAG
header somewhere inside ... nice for Linux hacks later on :)

Dave





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