MC68020CRC20E Freescale Semiconductor, MC68020CRC20E Datasheet - Page 47

• Manufacturer Part Number: MC68020CRC20E
• Description: IC MICROPROCESSOR 32BIT 114-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68020CRC20E

• Processor Type: M680x0 32-Bit
• Speed: 20MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 114-PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

F—Freeze Cache
E—Enable Cache
4.3.2 Cache Address Register (CAAR)
The format of the 32-bit CAAR is shown in Figure 4-3.
Bits 31–8, 1, and 0—Reserved
Index Field
4–4
31
The F-bit is set to freeze the instruction cache. When the F-bit is set and a cache miss
occurs, the entry (or line) is not replaced. When the F-bit is clear, a cache miss causes
the entry (or line) to be filled. A reset operation clears the F-bit.
The E-bit is set to enable the instruction cache. When it is clear, the instruction cache is
disabled. A reset operation clears the E-bit. The supervisor normally enables the
instruction cache, but it can clear the E-bit for system debugging or emulation, as
required. Disabling the instruction cache does not flush the entries. If the cache is
reenabled, the previously valid entries remain valid and may be used.
These bits are reserved for use by Motorola.
The index field contains the address for the “clear cache entry” operations. The bits of
this field, which correspond to A7–A2, specify the index and a long word of a cache line.
Freescale Semiconductor, Inc.
Figure 4-3. Cache Address Register
For More Information On This Product,
RESERVED
M68020 USER’S MANUAL
Go to: www.freescale.com
8
7
INDEX
2
MOTOROLA
RESERVED
1
0