[ECOS] RedBoot porting

Lewin A.R.W. Edwards larwe@larwe.com
Mon Jan 8 07:40:00 GMT 2001

>That's the main reason I'm thinking about running RedBoot from
>RAM (copy from ROM on startup).  Updating flash while you're
>running from it is a royal pain.

Is it even possible? The flash chips I use will only return status while in 
program mode, you can't exec code out of them while programming them.

The way I handle flash updates in the current program is to (on boot) check 
removable media for an upgrade file. If one is found, I load the whole 
caboodle into RAM, verify its checksum, disable all interrupts and other 
things, and then jump right into the loaded program (which is a standalone 
OS of its own). I erase and program the flash as quickly as possible then 
reset the machine. The beauty of this system is that it can be used to 
autoboot other things, e.g. it can be used for very quick tests of new OSs 
and third-party add-on modules on the real hardware platform.

It's akin to booting a PC off floppy :)

=== Lewin A.R.W. Edwards (Embedded Engineer)
Work: http://www.digi-frame.com/
Personal: http://www.zws.com/ and http://www.larwe.com/

"Und setzet ihr nicht das Leben ein,
Nie wird euch das Leben gewonnen sein."

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