[U-Boot-Users] boot up u-boot from RAM

[Nghiem, Tien]

Lei,

You have to rebuild your code to put your code in the RAM area (other than the FLASH area). Don't use the address 0x00-0x2fff because its reserved for the exception vectors usually. I have a Lite5200 EVB. I use the address 0x20000 to put my u-boot in RAM and it works. I don't know if it could be done for the mpc8270.

Tien

-----Original Message-----
From: u-boot-users-bounces at lists.sourceforge.net
[mailto:u-boot-users-bounces at lists.sourceforge.net]On Behalf Of Lei Sun
Sent: Thursday, October 26, 2006 4:15 PM
To: u-boot-users at lists.sourceforge.net
Subject: [U-Boot-Users] boot up u-boot from RAM


Hi all:
   I am debugging a costomized board based on mpc8270, due to the
design flaw, we can't boot up the system using flash, so I was trying
to debug u-boot by loading it into the RAM.
  I used JTAG debugger to initialize the SDRAM and load the u-boot to
0x0, after reset, the PC is at 0x100. the disassembled code looks
correct on that location, however, i can't single step start from
0x100. Is that because 0x100 is the reset vector ? I tried to put some
breakpoint at some places not far from start point, but it gave me
"unknown halt at 0x00000000" error after "run" command. after that the
memory seems corrupted.
  Too bad I was using a bad debugger(Guardian-SE),  I have a
evaluation copy of the codewarrior plus USB+TAP from freescale. I
tried that on our PQ2FADS-VR SDK. After reset, and CPU halt, I can't
see any disassembed code on 0x100 (the uboot is already in the flash,
and I assume it should read data from CS0 upon reset). Although the
code does execute after hitting "run" button.  I wonder why can't I
see the disassembed code after reset?

Thanks
lei

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