CDCLVD110A

SCAS841C – FEBRUARY 2007 – REVISED NOVEMBER 2009

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SPECIFICATION OF CONTROL REGISTER

The CDCLVD110A has an 11-bit, serial-in shift register and an 11-bit control register. The control Register

enables/disables each output clock, and selects either CLK0 or CLK1 as the input clock. The CDCLVD110A has

two modes of operation:

Programmable Mode (EN=1)

The shift register uses a serial input (SI) and a clock input (CK). Once the shift register is loaded with 11

clock pulses, the 12th clock pulse loads the control register. The first bit (bit 0) on SI enables the Q9-Q9

output pair, and the 10th bit (bit 9) enables the Q0-Q0 pair. The 11th bit (bit 10) on SI selects either CLK0 or

CLK1 as the input clock; a bit value of 0 selects CLK0, whereas a bit value of 1 selects CLK1. To restart the

control register configuration, a reset of the state machine must be done with a clock pulse on CK (shift

register clock input) and EN set to low. The control register can be configured only once after each reset.

Standard Mode (EN=0)

In this mode, the CDCLVD110A is not programmable and all the clock outputs are enabled. The clock input

(CLK0 or CLK1) is selected with the SI pin, as is shown in the table entitled control register.

STATE-MACHINE INPUTS

EN

SI

CK

OUTPUT

L

L

X

All outputs enabled, CLK0 selected, control register disabled, default state

L

H

X

All outputs enabled, CLK1 selected, control register disabled

H

L

↑

First stage stores L, other stage stores data of previous stage

H

H

First stage stores H, other stage stores data of previous stage

L

X

Reset of state machine, shift and control registers

CONTROL REGISTER

BIT 10

BITS [0-9]

L

H

CLK0

H

H

CLK1

X

L

Outputs disabled

SERIAL INPUT (SI) SEQUENCE

BIT 10

BIT 9

BIT 8

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

CLK_SEL

Q0

Q1

Q2

Q3

Q4

Q5

Q6

Q7

Q8

Q9

TRUTH TABLE FOR CONTROL LOGIC

CK

EN

SI

CLK0

CLK0

CLK1

CLK1

Q(0-9)

Q(0-9)

L

L

L

L

H

X

X

L

H

L

L

L

H

L

X

X

H

L

L

L

L

Open

Open

X

X

L

H

L

L

H

X

X

L

H

L

H

L

L

H

X

X

H

L

H

L

L

L

H

X

X

Open

Open

L

H

All outputs enabled

X = Don't care

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