Re: [ECOS] Redboot with big block flashes and small amounts of ram

[Jonathan Larmour <jifl at eCosCentric dot com>]

Rycerz Roman-G11565 wrote:
> Thanks for the info..
>
> We make powertrain control modules for automobiles and trucks.  
> What I am trying to do is to use eCos/Redboot to give us some early software
> so we can begin functional testing of modules.
> And have the ability to port to different platforms easily....  eCos/Redboot
> seems to make that possible. Before the modules ship to customers the code
> is replaced with engine strategy.  

40K of RAM is going to be tricky for RedBoot at the best of times anyway - 
stuff like the GDB stub can use multiple surprisingly large buffers, and 
it all adds up. I suspect you should try and do an eCos only application 
and use the flash drivers directly from that..... even then you will need 
to make changes to the flash drivers to avoid the read/modify/write of 
whole sectors at a time, but instead erasing a sector and then just 
writing multiple small bits.

If you do need RedBoot's loading abilities, you could either copy the code 
from it, or make modifications to it, e.g. how it programs the flash so 
that it does it in small amounts as data arrives. It will be a fair few 
changes though.

Jifl

> -----Original Message-----
> From: Gary D. Thomas [mailto:gary.thomas@mind.be] 
> Sent: Friday, April 25, 2003 9:37 AM
> To: Rycerz Roman-G11565
> Cc: ecos-discuss (E-Mail)
> Subject: Re: [ECOS] Redboot with big block flashes and small amounts of ram
>
>
> On Wed, 2003-04-23 at 20:47, Rycerz Roman-G11565 wrote:
>
> > Hi
> >
> >    I have a platform with 2.5meg of flash and only 40k of ram.  The 
> > external flash has 256k blocks.... Reboot as part of it setting up a 
> > workspace for flashing tries to
> >    allocate enough ram for a block.   Naturally it crashes...  Has anyone
> > had to deal with this situation before ????
>
>
> RedBoot has to perform read/modify/write access to the FLASH, so a 
> buffer at least as big as the FLASH erase block is required.  Also, 40KB of
> RAM would be really challenging to do much of anything with.
>
> What are you expecting to be able to do/run in this environment?
>
>
> >


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