Host USB issue on MPC8272

David Beamonte dbeamonte at
Tue Sep 9 00:24:48 EST 2008

I have checked that bit and it is not set. In fact, that register has 
the same value as the one in our ADS8272 (0x100c0000), which works.

Anyway, it must be an issue of this kind, from the beginning I have 
thought that we have a problem of arbitration of the bus that makes the 
processor hang when the CPMs try to access external memory. Can it be a 
problem of SDRAM configuration, wait-states or refresh times?

Thanks Scott,


Scott Wood escribió:
> David Beamonte wrote:
>> This issue seems to be related to one problem that we have always 
>> had. We can't configure buffers of SMCs, SCCs, etc, to be in SDRAM, 
>> because the processor hangs. We always have to configure buffers in 
>> DPRAM. In other drivers this has not been a problem, because the 
>> buffer size is not very large, so we can allocate it in DPRAM, but 
>> for this one, the buffer size is 0x8000 (32Kb) which exceeds DPRAM size.
>> Has anybody had the same problem? Can it be an USB specific problem 
>> or a general one?
> Make sure that BCR[PLDP] is not set, as per erratum SIU18.
> -Scott

More information about the Linuxppc-embedded mailing list