Efficient Embedding of
Deterministic Test Data
Mudassar Majeed1, Daniel Ahlström1, Urban Ingelsson1,
Gunnar Carlsson2 and Erik Larsson1
1Department
of Computer and
Information Science, Linköping
University, Sweden
2Ericsson
AB BU Networks
SE-164 80 Stockholm
Sweden
Purpose
 Printed Circuit Boards (PCBs) include an increasing number of
integrated circuits (ICs), often of the same type
 Example:
 Ericsson telecommunication systems contain PCBs with 36 ICs where 4
ICs are of type A, 8 ICs of type B, 8 ICs of type C and 16 ICs of type D
 In-field testing is needed due to harsh environment
 For in-field test, the problem is to deliver test data to the system
 Straight forward solution is to store test data in the system
 Drawbacks:

High memory requirements

Inflexibility in applying different tests
 The proposed solution uses an embedded test controller to
manipulate test data by exploiting structural information of the system
 Benefits: Reduces memory requirements and provides flexibility
2
Efficient Embedding of Deterministic Test Data
Outline
 Introduction
 Proposed Solution
 Experiments and Results
 Conclusions
MARKERINGSYTA FÖR BILDER
När du gör egna slides, placera
bilder och andra illustrationer
inom dessa fält. Titta gärna i
”baspresentationen” för
exempel på hur placeringen kan
göras.
3
Need for Remote System Test


Flexibility in applying commands
Embedded test solution
Test Engineer at Office
System at Remote Location
4
Introduction
Embedded Test Solution
Command 1:
Test All Components
Command 2:
Test Only Component A
Embedded
Test
Solution
Test
Data
Components
A
B
B
Test
Resp.
PCB
5
Introduction
IEEE 1149.1 Standard
ICs connected serially (IEEE 1149.1)
A



B
B
IEEE 1149.1 Standard for PCB testing
Supports testing core logic
Instructions INTEST, BYPASS
6
Introduction
IC Under Test Using IEEE 1149.1 Standard
Test component A
Bypass component A
A
A
4 bits
1 bit
BYPASS
INTEST
Stimuli:
Instruction: INTEST A
1.
2.
BYPASS A
IEEE 1149.1
IR-scan: Set instruction
DR-scan: Apply (execute)
IR-scan defines the length of the 1149.1 chain
7
Introduction
System Under Test Using IEEE 1149.1 Std.
A
Command 1:
Test All Components
B
B
INTEST A INTEST B INTEST B
Test Vectors
A
Command 2:
Test Only Component A
B
INTEST A BYPASS B
B
BYPASS B
8
Introduction
Naive Embedded Test Controller
Command 1:
Test All Components
(INTEST A INTEST B INTEST B)
CPU
Command 2:
Test Only Component A
(INTEST A BYPASS B BYPASS B)
Memory
Embedded Test Solution
High memory requirements and inflexibility in applying the tests
9
Introduction
Outline
 Introduction
 Proposed Solution
 Experiments and Results
 Conclusions
MARKERINGSYTA FÖR BILDER
När du gör egna slides, placera
bilder och andra illustrationer
inom dessa fält. Titta gärna i
”baspresentationen” för
exempel på hur placeringen kan
göras.
10
Key Idea
Command 1: Test All Components
INTEST A INTEST B INTEST B
Command 2:Test Only Component A
INTEST A BYPASS B BYPASS B
1
2
Type A
Structural
Information
Command 1:
3
Concatenator
Type B
Command 2:
Memory
Command
Embedded Test Solution
Provides flexibility in applying the tests
11
Proposed Solution
1. Memory Requirements
Comparison
Memory
Naive approach
Memory
Proposed concatenation
approach
Reduces memory requirements
12
Proposed Solution
2. Structural Information
A
B
B
Structural Information
-
Types of components
Order of components in the system
Instruction Register Length
Data Register Length
Instructions
13
Proposed Solution
3. Concatenator
A
B
B
Steps for a given command:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Read structural information
Read component specific test stimuli
Concatenate the stimuli
Scan in instruction vector (if required)
Scan in and apply test vector
Scan out test response
Compare with expected response
If exit condition met, then terminate
Else repeat step 2
14
Proposed Solution
Outline
 Introduction
 Proposed Solution
 Experiments and Results
 Conclusions
MARKERINGSYTA FÖR BILDER
När du gör egna slides, placera
bilder och andra illustrationer
inom dessa fält. Titta gärna i
”baspresentationen” för
exempel på hur placeringen kan
göras.
15
Objectives
 To show that the approach works:
 We used a PC as test controller and an FPGA as system under test
 To see how memory requirements are reduced:
 Naive Approach vs Proposed Concatenation Approach (for test
command: “test all components”)
 We created systems using industrial circuits as ICs
% Reduction in
Memory Requirements
=
16
Experiments and Results
Industrial Circuits
Circuit
ckt-1
ckt-2
ckt-3
ckt-4
ckt-5
ckt-6
ckt-7
ckt-8
Length of Test
Patterns (bits)
11256
22216
9628
43414
26970
80000
20000
110000
Number of Test
Patterns
3768
2636
4927
1528
4899
2859
18027
18142
Test Data Volume (MBs)
5.51
6.98
5.65
7.91
15.75
27.27
42.98
237.9
Z. Wang and K. Chakrabarty. Test data compression for IP embedded cores using selective
encoding of scan slices. In Proc. International Test Conference (ITC), pp. 581--590, 2005.
17
Experiments and Results
Industrial Circuits
ckt-1
Set
ckt-2
ckt-3
# of Multiplications
ckt-4
ckt-5
ckt-6
ckt-7
ckt-8
Design
2
1
3
20
2
2
3
20
2
8
3
20
18
Experiments and Results
Percentage Reduction in Memory Requirements
Results
Set 8 (ckt-8, 237.6 MBs)
Set 7 (ckt-7)
Average
Set 1 (ckt-1)
MBs
5.51
Set 2 (ckt-2)
6.98
Set 3 (ckt-3) 5.65
Set 4 (ckt-4) 7.91
Set 5 (ckt-5) 15.75
Set 6 (ckt-6) 27.27
Set 7 (ckt-7) 42.98
Set 8 (ckt-8) 237.9
Average
Set 1 (ckt-1)
Number of Multiplications
19
Experiments and Results
Conclusions
 Printed Circuit Boards (PCBs) include an increasing number of
integrated circuits (ICs), often of the same type
 Systems fail in operation and require in-field testing
 Test data volume requires huge memory
 The proposed solution exploits,
 Structural Information of the system
 The fact that multiple components of the same type require same
test data
 The test data manipulation via an embedded test controller
 The reduction in memory requirements depends upon the
number of components of the same type
 Example:

Ericsson telecommunication systems contain PCBs with 36 ICs where 4
ICs are of type A, 8 ICs of type B, 8 ICs of type C and 16 ICs of type D
20
Efficient Embedding of
Deterministic Test Data
Mudassar Majeed1, Daniel Ahlström1, Urban Ingelsson1,
Gunnar Carlsson2 and Erik Larsson1
1Department
of Computer and
Information Science, Linköping
University, Sweden
2Ericsson
AB BU Networks
SE-164 80 Stockholm
Sweden