T0131-01

P

S

P

t

(BUS)

t

su(SDATA)

t

h(SDATA)

t

r(SDATA)

t

f(SDATA)

SCLK

SDATA

V

IH(SM)

V

IH(SM)

V

IL(SM)

V

IL(SM)

A

Bit7(MSB)

Bit6

Bit0(LSB)

t

su(START)

t

h(START)

t

w(SCLL)

t

w(SCLH)

t

r(SM)

t

su(STOP)

t

f(SM)

SMBus Hardware Interface

9

10

SDATA

SCLK

SMBHost

CDCE706

C

BUS

C

BUS

R

P

R

P

S0376-01

CDCE706

SCAS815I – OCTOBER 2005 – REVISED NOVEMBER 2008 ........................................................................................................................................... www.ti.com

Block-Read Programming Sequence

1

7

1

1

8

1

1

7

1

1

S

Slave Address

Wr

A

CommandCode

A

Sr

Slave Address

Rd

A

8

1

8

1

8

1

1

Byte Count N

A

Data Byte 0

A

- - - - -

Data Byte N – 1

NA

P

Figure 10. Block-Read Protocol

Figure 11. Timing Diagram, Serial Control Interface

Figure 12 shows how the CDCE706 clock synthesizer is connected to the SMBus. Note that the current through

the pullup resistors (Rp) must meet the SMBus specifications (minimum 100 µA, maximum 350 µA). If the

CDCE706 is not connected to the SMBus, the SDATA and SCLK inputs must be connected with 10-k

Ω resistors

to VCC to avoid floating input conditions.

Figure 12. SMBus Hardware Interface

14

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