On Fri, 03 Jan 2003 21:19:36 +0800, Laudney Ren bren@sjtu.edu.cn writes:
I was very very very moved when I found you wrote such a detailed answer, providing so much background information, which would be precious to this list.
OK, thanks very much - it appears I didn't waste my time after all.
Just one thing ...
When MPC8xx is reset, it starts to execute machine code at 0x100.
In fact, it might execute at 0xfff00100 or 0x00000100 depending on the way your board designer has configured the hard reset (I think this is correct for 8xx - I'm mainly 8260 these days and I have to think back).
That's the nice thing about this trick - it doesn't matter if it's executing high or low at hard reset - we will relocate to the final address that the flash is located at and it's all configurable.
It's like a row of bricks which are the same. It makes no difference that which one you are standing on. Until the moment, in section _in_flash, we take away all the other bricks except one. If we haven't stood on the finally chosen brick, we'll fall. That's exactly what "disappear underneath" means.
Nice analogy :-) Cheers! Murray... -- Murray Jensen, CSIRO Manufacturing & Infra. Tech. Phone: +61 3 9662 7763 Locked Bag No. 9, Preston, Vic, 3072, Australia. Fax: +61 3 9662 7853 Internet: Murray.Jensen@csiro.au
Hymod project: http://www.msa.cmst.csiro.au/projects/Hymod/
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