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Functional Description
ARM DDI 0414C
Copyright © 2008 ARM Limited. All rights reserved.
2-15
Restricted Access
Non-Confidential
2.2
Functional operation
The functional operation is described in:
•
•
2.2.1
Timing
A 58-bit instruction, loaded serially at the start of each test, controls the operation of the
MBIST controller. Chapter 3
describes how to write the
instruction.
The timing diagrams in this section show the clock running at two different speeds:
•
the slower clock relates to the clock driven by your ATE
•
the faster clock relates to the clock driven by an on-chip
Phase Locked Loop
(PLL).
If you do not have an on-chip PLL, both clocks relate to the clock driven by your ATE.
Timing diagrams in the following sections show the procedures for operating the
MBIST controller:
•
•
•
•
Instruction load
To load an MBIST instruction, drive
MBISTSHIFT
HIGH. At the next rising clock
edge, the 58-bit shift sequence begins as shown in Figure 2-15. To enable data input
from the ATE, the PLL is in bypass mode, and the clock is not running at test frequency.
Figure 2-15 Loading the MBIST controller instruction
i[0]
i[1]
i[57]
CLK
MBISTRUN
MBISTSHIFT
MBISTDATAIN