MOTOROLA
Chapter 11. Secondary (L2) Cache Support
11-3
Part III. The Hardware Interface
are serviced just as they are for copy-back mode. Write-through mode sacriÞces some of
the write performance of copy-back mode, but guarantees L2 cache coherency with main
memory.
Since write-through mode keeps memory coherent with the contents of the L2 cache, there
is never any need to perform an L2 copy-back. This removes the need for the L2 cache to
maintain a dirty bit in the tag RAM (all cache blocks are unmodiÞed) and it also removes
the need for bus arbitration signals.
The L2 cache is conÞgured for write-through mode by pulling down itÕs WT signal. There
are no conÞguration changes to the MPC8260 required in write-through mode. The
MPC8260 can also support additional bus masters (60x or MPC8260 type) in write-through
mode.
Figure 11-2 shows a MPC8260 connected to a MPC2605 integrated L2 cache in write-
through mode.
Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
Page 490: ...14 36 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 524: ...17 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
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Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
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