[U-Boot-Users] data bus bit reversal
I have a question that isn't strictly related to U-Boot. I hope it's not unacceptable.
The old PPCBoot source included a macro used during Flash programming on a Musenki board (I suppose the U-Boot code still contains this, but I haven't checked). The macro uses a look-up table to reverse the bits within a byte--MSB to LSB, LSB to MSB, and so forth.
We have a custom MPC8241 board with the same problem: the lines on the 8-bit data bus between the PPC and the Flash device are reversed. We're using an AMC/Metrowerks PowerTAP PRO for debugging and Flash programming, and it appears that there is no way to have the built-in Flash programming algorithms compensate for the bit reversal.
My question is this: are there other Flash programmers (such as the one in the BDI2000) that can indeed compensate for the bit reversal?
My current plan is to use custom Flash programming code running in SDRAM, but it would be nice if there was a tool that let me bypass this process.
Again, I hope this message isn't too far off-topic. Thanks for any help.
-Robert DeLaGarza
In message 01C2F78D.563A35A0.robdlg@att.net you wrote:
I have a question that isn't strictly related to U-Boot. I hope it's not unacceptable.
This is perfectly ok. I could not think of a better place to ask, either.
The old PPCBoot source included a macro used during Flash programming on a Musenki board (I suppose the U-Boot code still contains this, but I haven't
It should still be there. At least I'm not aware that it was thrown out.
My question is this: are there other Flash programmers (such as the one in the BDI2000) that can indeed compensate for the bit reversal?
The standard firmware for the BDI2000 does not provide this feature. But I know that Abatron provided such a solution as part of their excellent support - within less than a day AFAIR.
I guess this solution is still available.
My current plan is to use custom Flash programming code running in SDRAM, but it would be nice if there was a tool that let me bypass this process.
We encountered similar problems before; this is one of the very few cases where I think that starting with a version of U-Boot that gets loaded to RAM first actually makes sense.
Again, I hope this message isn't too far off-topic. Thanks for any help.
You are welcome.
Best regards,
Wolfgang Denk
participants (2)
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DeLaGarza, Robert -
Wolfgang Denk