valid

valid

valid

valid

LSB

LSB+1

LSB +2

MSB

FIGURE 3. SCAN COUNTER & DECODER OUTPUTS TIMING DIAGRAM

SCAN RESET

ENABLE

SCAN

ST1 (int.)

ST2 (int.)

ST3 (int.)

ST4 (int.)

ST5 (int.)

ENABLE (int.)

CASCADE ENABLE

DATA OUTPUTS

FIGURE 4. COUNTER TIMING DIAGRAM

RESET

COUNT

LOAD

A

EN SC RESET SC

CE

B

EN SC RESET SC

CE

C

EN SC RESET SC

CE

OUTPUT DATA BUS

ENABLE

SCAN RESET

SCAN

FIGURE 5.

ILLUSTRATION OF A 3 DEVICE CASCADE

END OF SCAN

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