Integrated Memories
5-4
ColdFire2/2M User’s Manual
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MOTOROLA
5.1.3.5 INSTRUCTION CACHE DATA STROBE (ICHD_ST).
read or write cycle to the cache data RAM on a low-to-high transition. This signal should be
connected to the strobe input (ST) signal of the compiled cache data RAM.
This output signal initiates a
5.1.3.6 INSTRUCTION CACHE DATA READ/WRITE (ICHD_RWB).
indicates the direction of the data transfer to the cache data RAM. A high level indicates a
read cycle and a low level indicates a write cycle. It should be connected to the read/write
(RWB) signal of the compiled cache data RAM.
This output signal
5.1.3.7 INSTRUCTION CACHE SIZE (ICH_SZ[2:0]).
of the compiled cache RAMs connected to the ColdFire2/2M.
Table 5-1
lists the possible
cache configurations. ICH_SZ[2:0] does not affect the CACR in any way; thus a MOVEC
instruction will write the CACR regardless of the ICH_SZ specification (which is contrary to
the RAM_SZ and ROM_SZ effect during RAMBAR and ROMBAR loading).
These static inputs specify the size
5.1.3.8 INSTRUCTION CACHE TAG CHIP-SELECT (ICHT_CSB).
signal indicates the cache tag RAM is currently selected to perform a data transfer with the
ColdFire2/2M. This signal should be connected to the chip-select (CSB) signal of the
compiled cache tag RAM.
This
active-low output
5.1.3.9 INSTRUCTION CACHE TAG INPUT BUS (ICHT_DI[31:8]).
provide the write data path between the ColdFire2/2M and the cache tag RAM. The data bus
depends upon the size of the CACHE; see
Table 5-1
. Bit eight is always the valid bit and is
always used as seen in the cache configuration shown in
Table 5-2
. This bus should be
connected to the data inputs (DBI) of the compiled cache tag RAM. Functionally,
MADDR[31:9] is written onto ICHT_DI[31:9] and ICHT_DI[8] is written with the valid state of
the entry.
These output signals
Table 5-1. Cache Configuration Encoding
ICACHE SZ
(BYTES)
None
512
1 K
2 K
4 K
8 K
16K
32K
NOTE: HPF65 ColdFire2 Hard Macro may require a reduced operating frequency for 16K and 32K sized
ICACHE.
ICH_SZ[2:0]
TAG ARRAY
SIZE
-
32x24
64x23
128x22
256x21
512x20
1Kx19
2Kx18
TAG ARRAY
ADDRESS
-
ICH_ADDR[8:4]
ICH_ADDR[9:4]
ICH_ADDR[10:4]
ICH_ADDR[11:4]
ICH_ADDR[12:4]
ICH_ADDR[13:4]
ICH_ADDR[14:4]
DATA ARRAY
SIZE
-
128x32
256x32
512x32
1Kx32
2Kx32
4Kx32
8Kx32
DATA ARRAY
ADDRESS
-
ICH_ADDR[8:2]
ICH_ADDR[9:2]
ICH_ADDR[10:2]
ICH_ADDR[11:2]
ICH_ADDR[12:2]
ICH_ADDR[13:2]
ICH_ADDR[14:2]
000
001
010
011
100
101
110
111
F
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