[ECOS] How to build a executed-in-flash application?

wang cui iucgnaw@msn.com
Fri Sep 8 01:22:00 GMT 2006


Thank you, Bart.

Actually, I did think about the caveats you mentioned, and my product 
really need the "in the field update" function. That's why I need a ROM 
RedBoot and ROM applications. 
With the help of Andrew, I have done it.

Anyway, your reply clarifies this issue for me.

>From: Bart Veer <bartv@ecoscentric.com>
>To: iucgnaw@msn.com
>CC: ecos-discuss@sources.redhat.com
>Subject: Re: [ECOS] How to build a executed-in-flash application?
>Date: 07 Sep 2006 14:38:37 +0100
>
> >>>>> "Wang" == Wang Cui <iucgnaw@msn.com> writes:
>
>     Wang> As I know, normally RedBoot use startup type "ROM", and
>     Wang> application use startup type "RAM", then we can use RedBoot
>     Wang> "load" application into ram and "go" it.
>
>     Wang> On my target board, this method works pretty well now. But
>     Wang> since the ram size is only 512K, I want the application
>     Wang> image executed-in-place in the flash to save ram for usage.
>
>Having a ROM RedBoot and a RAM application is only one of the standard
>scenarios. If you want the application to run from flash then there
>should be no need to have RedBoot in the system at all. Instead
>configure eCos itself for ROM startup, link your application with
>that, and install it in place of RedBoot. The application now has
>control over all the hardware. The obvious caveats are:
>
>   1) you need some way of programming the flash without RedBoot. This
>      is likely to involve a hardware debug solution such as BDM or
>      jtag.
>
>   2) debugging applications in flash is generally a lot harder than
>      ones in RAM (although that is going to be a problem whenever code
>      resides in flash, irrespective of whether or not RedBoot is
>      involved).
>
>   3) upgrading an application in the field becomes more difficult.
>
>   4) not all platforms will be tested in this scenario. Depending on
>      your hardware there may be platform HAL issues.
>
>Andrew has been describing an alternative approach where RedBoot is
>still in use and the application resides in a non-standard location in
>flash. That can also be made to work, but having a ROM startup
>application would be more conventional.
>
>Bart
>
>--
>Bart Veer                       eCos Configuration Architect
>http://www.ecoscentric.com/     The eCos and RedBoot experts



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