MPC8544COMEDEV Freescale Semiconductor, MPC8544COMEDEV Datasheet - Page 303

• Manufacturer Part Number: MPC8544COMEDEV
• Description: KIT DEV EXPRESS MPC8544COM
• Manufacturer: Freescale Semiconductor
• Type: MPUr

Specifications of MPC8544COMEDEV

• Contents: Board
• For Use With/related Products: MPC8544
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

An effective value of each PLRU bit is calculated as follows:
These effective PLRU bits are used to select a victim, as indicated in
7.9
This section describes the behavior of the L1 and L2 cache in response to various operations and in various
configurations.
7.9.1
7.9.1.1
After power-on reset the valid bits in the L2 cache status array are in random states. Therefore, it is
necessary to perform a flash invalidate before using the array as an L2 cache. This is done by writing a one
to the L2I field of the L2 control register (L2CTL). This can be done before or simultaneously with the
write that enables the L2 cache. That is, the L2E and L2I bits of L2CTL can be set simultaneously. The
L2I bit clears automatically, so no further writes are necessary.
7.9.1.2
After power-on reset the contents of the data and ECC arrays are random, so all SRAM data must be
initialized before it is read. If the cache is initialized by the processor or any other device that uses
sub-cache-line transactions, ECC error checking should be disabled during the initialization process to
avoid false ECC errors generated during the read-modify-write process used for sub-cache-line writes to
the SRAM array. This is done by setting the multi- and single-bit ECC error disable bits of the L2 error
Freescale Semiconductor
P0_eff = f(P0,L0,L1,L2,L3,L4,L5,L6,L7) = (L0 & L1 & L2 & L3) | (P0 & ~(L4 & L5 & L6 & L7))
P1_eff = f(P1,L0,L1,L2,L3) = (L0 & L1) | (P1 & ~(L2 & L3))
P2_eff = f(P2,L4,L5,L6,L7) = (L4 & L5) | (P2 & ~(L6 & L7))
P3_eff = f(P3,L0,L1) = L0 | (P3 & ~L1)
P4_eff = f(P4,L2,L3) = L2 | (P4 & ~L3)
P5_eff = f(P5,L4,L5) = L4 | (P5 & ~L5)
P6_eff = f(P6,L6,L7) = L6 | (P6 & ~L7)
L2 Cache Operation
Initialization
MPC8544E PowerQUICC III Integrated Host Processor Family Reference Manual, Rev. 1
L2 Cache Initialization
Memory-Mapped SRAM Initialization
Way Selected
Table 7-25. PLRU-Based Victim Selection Mechanism
W0
W1
W2
W3
W4
W5
W6
W7
Effective PLRU
State (Binary)
00x0xxx
00x1xxx
01xx0xx
01xx1xx
1x0xx0x
1x0xx1x
1x1xxx0
1x1xxx1
(using effective PLRU bits)
Reduced Logic Equation
~P0 & ~P1 & ~P3
~P0 & ~P1 & P3
~P0 & P1 & ~P4
P0 & ~P2 & ~P5
P0 & ~P2 & P5
P0 & P2 & ~P6
~P0 & P1 & P4
P0 & P2 & P6
Table
7-25.
L2 Look-Aside Cache/SRAM
7-33