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 <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
CC: [EMAIL PROTECTED]
Subject: Re: [ECOS] How to build a executed-in-flash application?
Date: 07 Sep 2006 14:38:37 +0100
>>>>> "Wang" == Wang Cui <[EMAIL PROTECTED]> 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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