Re: u-boot or equivalent for MCF52223

On Apr 2, 2008, at 1:14 PM, Seymour David wrote:

> Hi Rick,
> I imagine that U--boot might be too big for the MCF52223 family's
> on-chip memory of 256KB flash and 32KB RAM. But I do not know that fir
> sure.

u-boot will fit into the flash, for sure.
RAM may be a little tight, but it could probably do it.
but I'm wondering why you'd want to run u-boot on this small cpu.

> The dBUG ROM monitor is ported to the MCF5213 (same memory config) and
> support s-record downloades.  You can prune it further to only support
> the serial download and flash programming.


> Can anyone direct me to an implementation of u-boot or an equivalent
> boot
> loader for the MCF52223?  Specifically I'm looking for some help
> reprogramming the onboard flash through a serial port.  I'm currently
> doing
> this for a MCF5206e, but I load the whole flash image into external  
> RAM
> first.  The MCF52223 does not have an external bus, so no external  
> RAM.
> U-boot looks like an option, but I haven't found a port to this
> processor.
>
> Thanks,
>
> Rick Cordray



Well hm.

How about EzPort?

"Flash memory may also be programmed via the EzPort, which is a  
serial flash memory programming interface that allows the flash  
memory to be read, erased and programmed by an external controller in  
a format compatible with most SPI bus flash memory chips. "

Is that an option?

Alternatively, from a quick glance at the reference manual, it  
appears that the flash is organized into 8K blocks. 8K < 32K, so you  
have enough RAM left over to run dBUG, and buffer at least 2, maybe 3  
blocks worth of flash at a time. Ugly and slow, but would work.

Alternatively, have you considered loading the flash via the BDM?

-
allon