[previous] [next] [contents]    Information required to test the full BST interconnects

This demonstration board includes 24 full-BS interconnects, two of which (nets 10 and 11 in figure 5.1) share their BS cells between the two BS chains. The information required for test program generation is once more obtainable from the SN74BCT8244 data sheet and from the board structural information (netlist), and comprises the following fields for each interconnect:
  • Number and identification of the BS chains that have cells present in this interconnect

Concerning the output pins present:

  • Number of output pins and (for each one) location, in the BS chain, of the output cell, the control cell (if any) and the logic value that drives the pin to the high-impedance state.

Concerning the input pins present:

  • Number of input pins and (for each one) location, in the BS chain, of the input cell.

Concerning the bidirectional pins present:

  • Number of bidirectional pins and (for each one) location, in the BS chain, of the output cell, the input cell, the control cell and the logic value that drives the pin to the high-impedance state.

Concerning the primary input pins present (it is assumed that each primary input pin is driven by an external test channel that enables the primary input to be set to the high-impedance state):

  • Number of primary input pins and (for each one) an identification number and the control value that drives the respective test channel to the high-impedance state.

Concerning the primary output pins present:

  • Number of primary output pins and (for each one) an identification number.

Finally, and considering the possible case of interconnects that tie unused input pins to ground or VCC:

  • Is the interconnect at a fixed logic level and if so at which logic value?

The information required for generating the test program segment concerning the full-BS interconnects, in our demonstration board, is presented in table 1.
 

Net ident. # BS chains BS chain ident. # of output pins Output cell Control cell High imped. # of input pins Input cell # of bidir. pins # of prim. inputs Prim. input High imped. # of prim. outputs Prim. output Fixed level? Logic level
Net 0

1

0

0

-

-

-

1

2

0

1

0

0

0

-

No

-

Net 1

1

0

0

-

-

.

1

3

0

1

1

0

0

-

No

-

Net 2

1

0

0

-

-

.

1

4

0

1

2

0

0

-

No

-

Net 3

1

0

0

-

-

.

1

5

0

1

3

0

0

-

No

-

Net 4

1

0

0

-

-

.

1

6

0

1

4

0

0

-

No

-

Net 5

1

0

0

-

-

.

1

7

0

1

5

0

0

-

No

-

Net 6

1

0

0

-

-

.

1

8

0

1

6

0

0

-

No

-

Net 7

1

0

0

-

-

.

1

9

0

1

7

0

0

-

No

-

Net 8

1

0

0

-

-

.

1

0

0

0

-

-

0

-

Yes

0

Net 9

1

0

0

-

-

.

1

1

0

0

-

-

0

-

Yes

0

Net 10

2

0

1

16

1

1

0

-

0

0

-

-

0

-

No

-

   

1

0

-

-

-

1

8

0

             
Net 11

2

0

1

17

1

1

0

-

0

0

-

-

0

-

No

-

   

1

0

-

-

-

1

9

0

             
Net 12

1

0

0

-

-

-

1

18

0

0

-

-

0

-

Yes

0

Net 13

1

0

0

-

-

-

1

19

0

0

-

-

0

-

Yes

0

Net 14

1

1

1

-

-

-

1

0

0

0

-

-

0

-

Yes

0

Net 15

1

1

1

-

-

-

1

1

0

0

-

-

0

-

Yes

0

Net 16

1

1

1

10

0

1

0

-

0

0

-

-

1

0

No

-

Net 17

1

1

1

11

0

1

0

-

0

0

-

-

1

1

No

-

Net 18

1

1

1

12

0

1

0

-

0

0

-

-

1

2

No

-

Net 19

1

1

1

13

0

1

0

-

0

0

-

-

1

3

No

-

Net 20

1

1

1

14

1

1

0

-

0

0

-

-

1

4

No

-

Net 21

1

1

1

15

1

1

0

-

0

0

-

-

1

5

No

-

Net 22

1

1

1

16

1

1

0

-

0

0

-

-

1

6

No

-

Net 23

1

1

1

17

1

1

0

-

0

0

-

-

1

7

No

-

Table 1: Information required to generate the test program for full-BS interconnects.