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Functional Description
ARM DDI 0414C
Copyright © 2008 ARM Limited. All rights reserved.
2-13
Restricted Access
Non-Confidential
MBIST controller block top level I/O
The top level I/O of the MBIST controller contains the Cortex-A9 processor interface.
See Appendix A
and the inputs and outputs shown in Table 2-8.
Note
The reset signals of the Cortex-A9 processor must be HIGH in MBIST test mode.
Because the MBIST test mode uses some functional paths to access RAMs, the registers
on those paths have to be out of reset.
The following signals have additional information:
SE
Preservation of array state is required when performing multiload
Automatic Test Pattern Generator
(ATPG) runs or when performing
IDDQ
testing. After performing MBIST tests to initialize the arrays to a
required background, the ATPG test procedures must assert
SE
during all
test setup cycles in addition to load/unload. Any clocking during
IDDQ
capture cycles must have array chip select signals constrained.
MBISTRESULT[5:0]
During tests, the
MBISTRESULT[1]
signal indicates failures. You can
operate using two modes, by configuring bit [5] of the engine control
section of the instruction register. If bit [5] is set, the
MBISTRESULT[1]
Table 2-8 MBIST controller top level I/O
Signal
Direction
Function
Value, MBIST mode
Value, function mode
MBISTDATAIN
Input
Serial data in
Toggle
0
MBISTDSHIFT
Input
Data log shift
Toggle
0
nRESET
Input
MBIST reset
Toggle
0
a
MBISTRESULT[5:0]
Output
Output status bus
Strobe
-
MBISTRUN
Input
Run MBIST test
Toggle
0
MBISTSHIFT
Input
Instruction shift
Toggle
0
MBISTENABLE
Input
MBIST path enable
Toggle
0
SE
Input
ATPG signal
0
0
a.
nRESET
and
MBISTENABLE
must be LOW in functional mode.