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SERIAL INTERFACE

Serial Interface Operation Requirement

Serial Interface Device Address

CDCD5704

SCAS823 – DECEMBER 2006

Table 1. TERMINAL FUNCTIONS

TERMINAL

TYPE

DESCRIPTION

NAME

NO.

BYPASS

14

Input

If 0, the PLL is bypassed and the PLL is switched off.

CLK0

27

Output

Output for Clock0

CLK0B

26

Output

Complementary output for Clock0

CLK1

24

Output

Output for Clock1

CLK1B

23

Output

Complementary output for Clock1

CLK2

20

Output

Output for Clock2

CLK2B

19

Output

Complementary output for Clock2

CLK3

17

Output

Output for Clock3

CLK3B

16

Output

Complementary output for Clock3

EN

11

Input

Output enable; if 0, all outputs are disabled.

ID0

12

Input

Device ID, bit 0

ID1

13

Input

Device ID, bit 1

ISET

3

Output

Set clock driver current with external resistor

REFCLK

5

Input

Reference clock input

REFCLKB

6

Input

Complementary reference clock input

SCL

9

Input

Serial interface clock, 3.3-V compatible

SDA

10

Input

Serial interface data, 3.3-V compatible

VDD

15, 22, 28

Power

2.5-V power supply for outputs

VDDC

7

Power

2.5-V power supply for core

VDDP

1

Power

2.5-V power supply for PLL

VSS

4, 18, 21, 25

Ground

Ground

VSSC

8

Ground

Ground for core

VSSP

2

Ground

Ground for PLL

The following section describes the serial interface programming. In general, the serial interface slave supports

The internal timing of the serial interface logic block in the CDCD5704 requires a timing reference derived from

the input clock (REFCLK). A reference clock must be present at the REFCLK pin for the serial interface to be

operational.

A6

A5

A4

A3

A2

A1

A0

W/R

1

1

0

1

1

ID1

ID0

0/1

The device-ID is determined by the external pins ID0 and ID1. They are part of the device 8-bit address.

Therefore, four different devices (00, 01, 10, and 11) can be addressed via the same serial interface. The least

significant bit of the address designates a write or read operation.

R/W Bit:

0 = write to CDCD5704 device

1 = read from CDCD5704 device

3

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