
Chapter 12. Test
12-15
Test Wrapper
Figure 12-12. CF4eTW to Non-Core Delay Scan Vector Example
12.2.4.4 CF4eTW Testing of Noncore Outputs
The CF4eTW wrapper scan capture mode operates independently of the CF4e core scan
architecture. The CF4eTW can be appended to the noncore logic to become the capture part
of its test structure. Using the CF4eTW to launch or capture logic values associated with
the noncore logic requires the use of a gate-level netlist of the CF4eTW to be included as
part of the noncore logic netlist when vector generation is to be accomplished.
Wrapper scan capture mode uses the CF4eTW’s ability to capture logic values or logic
transition values launched from the noncore logic. The CF4eTW can be operated
coincidentally with the noncore logic test structures and can be used to enable structural
testing or timing delay testing.
clkfast
wsei
Last Scan Shift In
First Scan Shift Out
Functional
Sample
Registered
CF4eTW
Output
Data
Data
Register Setup
Time Point
for Noncore Logic
to Wrapper
tbseo
Data
Data
Noncore
Logic Input
Register
Data
Data
Data
Data
Note: inputs not
required for
this example
Noncore Logic
Input Register
Sample Point
tbte
Shifting will apply
the necessary
logic values
N-1 Scan Shift In
To apply values
from non-registered
CF4eTW output
signals
Logic
Transition
Data
Opposite
Transition
Capture
Path
non-core
Scan SE
F
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