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Functional Description
ARM DDI 0414C
Copyright © 2008 ARM Limited. All rights reserved.
2-5
Restricted Access
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Instruction data and Data data RAMs
The Instruction data cache is selected using bits
MBISTARRAY[7:4]
. The Data data
cache is selected using bits
MBISTARRAY[16:13]
. This cache is byte-writable. All
write enable bits must be controllable separately.
Both data caches consist of eight RAM arrays. See
RAM arrays and MBIST controller
on page 2-2 for more information. For both data caches two arrays are tested
in parallel and the same data is sent to each CPU.
For
n=0
to
n=3
Data in and Data out buses are mapped as shown in Figure 2-1 and
Figure 2-1 Data In for Instruction data RAM and Data data RAM
Figure 2-2 Data Out for Instruction data RAM and Data data RAM
Instruction data RAMs have a word write enable, controlled by
MBISTWRITEEN
when in BIST mode.
Data data RAMs have a byte write enable, controlled by
MBISTBE[3:0]
as shown in
MBISTINDATA[63:0]
Data in [31:0] for array n+1
Data in [31:0] for array n
0
31
32
63
Data out
[31:0] for
array n+1
Data out
[31:0] for
array n
Data out
[31:0] for
array n+1
Data out
[31:0] for
array n
Data out
[31:0] for
array n+1
Data out
[31:0] for
array n
Data out
[31:0] for
array n+1
Data out
[31:0] for
array n
Data out [63:0] for
CPU3
Data out [63:0] for
CPU2
Data out [63:0] for
CPU1
Data out [63:0] for
CPU0
MBISTOUTDATA[255:0]
255
192 191
128 127
64 63
0
Table 2-3 Data data RAM byte write enable control
MBISTBE bit
Description
0
Byte 0, bits [7:0]