SN54ACT8997, SN74ACT8997

SCAN-PATH LINKERS WITH 4-BIT IDENTIFICATION BUSES

SCAN-CONTROLLED IEEE STD 1149.1 (JTAG) TAP CONCATENATORS

SCAS157D – APRIL 1990 – REVISED DECEMBER 1996

12

POST OFFICE BOX 655303

Table 6. DCO Function Table

DCI

INTERNAL

SIGNALS†

CONTROL-REGISTER BITS‡

DCO

IRERR

CE

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

X

X

X

X

X

X

X

0

0

X

H

X

X

X

X

X

X

X

1

0

X

Z

X

X

X

0

0

0

X

X

1

X

H

X

X

X

1

0

0

X

X

1

X

L

X

X

X

0

0

1

1

X

1

X

H

X

X

X

1

0

1

1

X

1

X

L

X

0

X

0

0

1

0

X

1

X

L in Pause-IR§, H otherwise

X

1

X

0

0

1

0

X

1

X

H

X

0

X

1

0

1

0

X

1

X

H in Pause-IR§, L otherwise

X

1

X

1

0

1

0

X

1

X

L

X

X

0

0

1

0

X

X

1

X

L

X

X

0

1

1

0

X

X

1

X

H

X

X

1

0

1

0

X

X

1

X

H

X

X

1

1

1

0

X

X

1

X

L

L

X

X

1

1

1

X

X

1

0

H

L

X

X

1

1

1

X

X

1

1

L

L

X

X

0

1

1

X

X

1

0

L

L

X

X

0

1

1

X

X

1

1

H

H

X

X

1

1

1

X

X

1

0

L

H

X

X

1

1

1

X

X

1

1

H

H

X

X

0

1

1

X

X

1

0

H

H

X

X

0

1

1

X

X

1

1

L

† These signals are generated as described elsewhere in this data sheet.

‡ The control register must contain these values after the TAP has passed through its most recent Update-DR state.

§ DCO becomes active on the falling edge of TCK as the TAP enters the Pause-IR state and becomes inactive on the

falling edge of TCK as the TAP enters Exit2-IR.