
Functional Description
2-6
Copyright © 2007, 2008 ARM Limited. All rights reserved.
ARM DDI 0402B
For a 16-way cache, you can remove one bit from the lower address range and add it to
the upper address range as compared to an 8-way cache of the same size. Table 2-3
shows the address range of the
MBISTADDR
bus used to test the data RAM, based on
the L2 cache size and configured to be 16-way.
The cache controller has a 256-bit wide
Line Read Buffer
(LRB) in each slave. One of
these holds data for MBIST testing. The cache controller always adds two register
delays to the MBIST data read path for the data RAM.
When using the MBIST controller you must account for the data RAM latency in the
pipeline. The latency can be from one to eight clock cycles. See
MBISTCE[0]
is for the chip enable to the data RAM.
The signal
MBISTDCTL[2:0]
is for reads from previous MBIST transactions.
Figure 2-3 on page 2-7 shows the cache controller MBIST paths for data RAM testing.
Table 2-3 MBISTADDR and MBISTDIN mapping for data RAM, 16-way
L2
cache
size
Number of
data RAM
indexes
MBISTADDR to data RAM mapping
MBISTDIN to data RAM mapping
256KB
8,192
DATAADDR[12:0]
=
MBISTADDR[19:16,10:2]
DATAWD[63:0]
=
MBISTDIN[63:0]
512KB
16,384
DATAADDR[13:0]
=
MBISTADDR[19:16,11:2]
DATAWD[63:0]
=
MBISTDIN[63:0]
1MB
32,768
DATAADDR[14:0]
=
MBISTADDR[19:16,12:2]
DATAWD[63:0]
=
MBISTDIN[63:0]
2MB
65,536
DATAADDR[15:0]
=
MBISTADDR[19:16,13:2]
DATAWD[63:0]
=
MBISTDIN[63:0]
4MB
131,072
DATAADDR[15:0]
=
MBISTADDR[19:16,14:2]
DATAWD[63:0]
=
MBISTDIN[63:0]
8MB
262,144
DATAADDR[16:0]
=
MBISTADDR[19:2]
DATAWD[63:0]
=
MBISTDIN[63:0]