[U-Boot-Users] comment in mpc8xx - cpu_init.c - line 76
Line 76 in the most up-to-date version of .../u-boot/cpu/mpc8xx/cpu_init.c tells me NOT to change EBDF. Do I need to stick to this... advice?
The Hard Reset Configuration word of my MPC875-powered hardware is hard-wired to set the SCCR[EBDF] to 01 (half bus speed) at hard reset in the moment. I had hoped that I could change SCCR[EBDF] to 00 (full bus speed) via software if needed.
So - is the comment in the code some kind of serious warning, for the CPU will burn or crash if I try to change EBDF via software, or may I ignore it? I'd need the hardware guys to put in some additional jumper in case I can't change SCCR[EBDF] by software for some reason.
Thanks for your time,
Peter Asemann
Dear Peter,
in message 41FA5969.4050107@web.de you wrote:
Line 76 in the most up-to-date version of .../u-boot/cpu/mpc8xx/cpu_init.c tells me NOT to change EBDF. Do I need to stick to this... advice?
No - if you know _exactly_ what you're doing.
So - is the comment in the code some kind of serious warning, for the CPU will burn or crash if I try to change EBDF via software, or may I ignore it? I'd need the hardware guys to put in some additional jumper
You must not ignore it. You have to understand what it means; for reference see "cpu/mpc8xx/speed.c"
Best regards,
Wolfgang Denk
participants (2)
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Peter Asemann -
Wolfgang Denk