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MPC106 PCIB/MC User's Manual
MOTOROLA
CF_FLUSH_L2—Setting this configuration parameter causes the internal L2 cache
controller to flush all modified lines to memory, and to invalidate all L2 cache lines.
This configuration parameter can also be accessed through port 0x81C. Note that an
L2 flush can only occur if the internal L2 cache controller is enabled.
Note that L2_UPDATE_EN, CF_FLUSH_L2, and L2_EN have no effect on the external
L2 cache controller operation. However, it is possible for the external L2 cache controller
to monitor these parameters at port 0x81C and use them to perform similar functions.
5.4.2 L2 Cache Interface Initialization Parameters
The L2 cache interface initialization parameters control the configuration and operational
behavior of the L2 cache interface, and can only be changed when the L2 cache interface
is disabled. These parameters must be set properly before the L2 cache is enabled and the
L2 cache interface must be disabled before modifying these parameters.
The L2 cache interface initialization parameters are as follows:
CF_CBA_MASK—Specifies which bits of the dirty address read from the tag RAM
are valid. For systems requiring less than 4 Gbytes of cacheable space, this
parameter allows the tag RAM width to be reduced. See Section 5.2.1, “L2 Cache
Addressing,” for more information on this parameter. Note that this parameter also
affects the external L2 cache controller interface.
CF_CACHE_1G—Specifies the memory space cached by L2 cache. Note that this
parameter also affects the external L2 cache controller interface.
CF_FAST_L2_MODE—Specifies if fast L2 mode timing is enabled. The use of fast
L2 mode is supported only by the 604. Note that this parameter also affects the
external L2 cache controller interface.
CF_DATA_RAM_TYPE—Specifies the type of SRAM used by the L2 cache.
CF_WMODE—Specifies L2 data RAM write timing and partial update mode. See
Section 5.4.2.4, “CF_WMODE,” for more information on this parameter.
CF_MOD_HIGH—Specifies the polarity of the DIRTY_IN, DIRTY_OUT, and TV
signals.
CF_HIT_HIGH—Specifies the polarity of the HIT signal for the internal L2 cache
controller interface only. Note that the HIT signal is always active low for the
external L2 cache controller interface, regardless of the state of CF_HIT_HIGH.
CF_ADDR_ONLY_DISABLE—Specifies whether the internal L2 controller
responds to address-only transactions (Clean, Flush, and Kill).
CF_HOLD—Specifies the hold time of the address, TV, and DIRTY_OUT signals
with respect to the rising edge of the TWE signal.