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