NH82801FBM S L89K Intel, NH82801FBM S L89K Datasheet - Page 780

• Manufacturer Part Number: NH82801FBM S L89K
• Manufacturer: Intel

Specifications of NH82801FBM S L89K

• Lead Free Status / RoHS Status: Compliant

Testability
24.1.1
780
Figure 24-2. Example XOR Chain Circuitry
Table 24-1. XOR Test Pattern Example
XOR Chain Testability Algorithm Example
XOR chain testing allows motherboard manufacturers to check component connectivity
(e.g., opens and shorts to VCC or GND). An example algorithm to do this is shown in
In this example, Vector 1 applies all 0’s to the chain inputs. The outputs being non-inverting will
consistently produce a 1 at the XOR output on a good board. One short to VCC (or open floating to
VCC) will result in a 0 at the chain output, signaling a defect.
Likewise, applying Vector 7 (all 1’s) to the chain inputs (given that there are an even number of
input signals in the chain), will consistently produce a 1 at the XOR chain output on a good board.
One short to VSS (or open floating to VSS) will result in a 0 at the chain output, signaling a defect.
It is important to note that the number of inputs pulled to 1 will affect the expected chain output
value. If the number of chain inputs pulled to 1 is even, then expect 1 at the output. If the number of
chain inputs pulled to 1 is odd, expect 0 at the output.
Continuing with the example in
sequence, the XOR Output will toggle between 0 and 1. Any break in the toggling sequence (e.g.,
“1011”) will identify the location of the short or open.
Vector
1
2
3
4
5
6
7
Vcc
Input
Pin 1
Input
Pin 1
0
1
1
1
1
1
1
Input
Pin 2
Input
Pin 2
0
0
1
1
1
1
1
Table
Input
Pin 3
24-1, as the input pins are driven to 1 across the chain in
Input
Pin 3
0
0
0
1
1
1
1
Intel
Input
Pin 4
®
I/O Controller Hub 6 (ICH6) Family Datasheet
Input
Pin 4
0
0
0
0
1
1
1
Input
Pin 5
Input
Pin 5
0
0
0
0
0
1
1
Input
Pin 6
Input
Pin 6
0
0
0
0
0
0
1
Output
Chain
XOR
Table
Output
XOR
1
0
1
0
1
0
1
24-1.