mcf5407 Freescale Semiconductor, Inc, mcf5407 Datasheet - Page 147

• Manufacturer Part Number: mcf5407
• Description: Mcf5407 Coldfire Integrated Microprocessor User
• Manufacturer: Freescale Semiconductor, Inc

4.10.2 Access Control Registers (ACR0–ACR3)
The ACRs, Figure 4-9, assign control attributes, such as cache mode and write protection,
to specified memory regions. ACR0 and ACR1 control data attributes; ACR2 and ACR3
control instruction attributes. Registers are accessed with the MOVEC instruction with the
Rc encodings in Figure 4-9.
For overlapping data regions, ACR0 takes priority; ACR2 takes priority for overlapping
instruction regions. Data transfers to and from these registers are longword transfers. Bits
12–7, 4, 3, 1, and 0 are always read as zeros.
11
10
9
8
7–0
Bits
IHLCK
IDCM
—
ICINVA
—
Name
The SIM MBAR region should be mapped as cache-inhibited
through an ACR.
Instruction cache half-lock.
0 Normal operation. The cache allocates to the lowest invalid way; if all ways are valid, the cache
1 Half cache operation. The cache allocates to the lowest invalid way of ways 2 and 3; if both of
This implementation allows maximum use of the available cache memory and also provides the
flexibility of setting IHLCK before, during, or after the needed allocations occur.
Instruction default cache mode. For normal operations that do not hit in the RAMBARs or ACRs,
this field defines the effective cache mode.
0 Cacheable
1 Cache-inhibited
Reserved, should be cleared.
Instruction cache invalidate. Invalidation occurs when this bit is written as a 1. Note the caches
are not cleared on power-up or normal reset.
0 No invalidation is performed.
1 Initiate invalidation of instruction cache. The cache controller sequentially clears all V bits.
Reserved. These bits must be cleared; otherwise, performance may be affected.
allocates to the way pointed at by the round-robin counter and then increments this counter
modulo-4.
these ways are valid, the cache allocates to way 2 if the high-order bit of the round-robin
counter is zero; otherwise, it allocates way 3 and then increments the round-robin counter
modulo-2. This locks the content of ways 0 and 1. Ways 0 and 1 are still updated on write hits
and may be pushed or cleared by specific cache push/invalidate instructions.
Subsequent local memory bus accesses stall until invalidation completes, at which point,
ICINVA is cleared automatically without software intervention. For copyback mode, use
CPUSHL before setting ICINVA.
Table 4-4. CACR Field Descriptions (Continued)
Chapter 4. Local Memory
NOTE:
Description
Cache Registers
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