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MPC8757 Memory Manager programming.

Question asked by Peter Goddard on Jan 4, 2012
Latest reply on Jan 8, 2012 by TomE

Hi,

    I'm probably answering my own question but I'm looking for clarification. It appears that the memory management registers BRx and ORx are defined in the datasheet in a bit reversed fashion. e.g. BRx bit 31 is the V bit and if that BRx is used, it should be set. However, a typical programming snippet is as below (taken from this website). I am certain that the LSB in the BR0 definition is in fact the Bit31 of the datasheet. So the programmed bits are a mirror image of the datasheet definition. Programmed bit 0 == datasheet bit 31, Programmed bit 1 == datasheet bit 30 etc. Is this correct and true for all other registers?

 

Thanks

Peter.

 

 //--------------------
 // BR0:  0xFF800801
 // OR0:     0xFF800774
 //--------------------
 lis  r4, 0xFF80  
 ori  r4, r4, 0x0801
 stw  r4, 0x100(r3) // BR0

 lis  r4, 0xFF80
 ori  r4, r4, 0x0774
 stw  r4, 0x104(r3) // OR0

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