5

www.pericom.com

P-0.1

02/27/13

PI6C49021

Low Power High Integration Clock Generator

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Serial Data Interface (SMBus)

PI6C49021 is a slave only SMBus device that supports indexed block read and indexed block write protocol using a single 7-bit ad-

dress and read/write bit as shown below.

Address Assignment

A6

A5

A4

A3

A2

A1

A0

W/R

1

1

0

1

0

0

1

0/1

How to Write

1 bit

8 bits

1

8 bits

1

8 bits

1

8 bits

1

8 bits

1

1 bit

Start

bit

D2H

Ack

Register

offset

Ack

Byte

Count = N

Ack

Data Byte

0

Ack

…

Data Byte

N - 1

Ack Stop bit

Note:

1.

Register offset for indicating the starting register for indexed block write and indexed block read. Byte Count in write mode cannot be 0.

Byte 0: Spread Spectrum Control Register

Bit

Description

Type

Power Up

Condition

Output(s)

Affected

Notes

7

OE for SE_66M0

RW

1

SE_66M0 output

0 = disabled

1 = enabled

6

Enable hardware or software control of OE bits

(see Byte 0-Bit 6 and Bit 5 Functionality table)

RW

0

All outputs

0 = hardware cntl

1 = software ctrl

5

Software RESET# bit. Enablea or disables all

outputs.

(see Byte 0-Bit 6 and Bit 5 Functionality table)

RW

1

All outputs

0 = disabled

1 = enabled

4

Reserved

R

Undefined

Not applicable

3

Reserved

R

Undefined

2

Reserved

R

Undefined

1

Reserved

R

Undefined

0

OE for SE_66M1

RW

1

SE_66M1 output

0 = disabled

1 = enabled

How to Read (M: abbreviation for Master or Controller; S: abbreviation for slave/clock)

1 bit

8 bits

1 bit

8 bits

1 bit

1 bit

8 bits

1 bit

8 bits

1 bit

8 bits

1 bit

…

8 bits

1 bit

1 bit

M:

Start

bit

M:

Send

"D2h"

S:

sends

Ack

M: send

starting

databyte

location:

N

S:

sends

Ack

M:

Start

bit

M:

Send

"D3h"

S:

sends

Ack

S:

sends

# of

data

bytes

that

will

be

sent:

X

M:

sends

Ack

S:

sends

start-

ing

data

byte

N

M:

sends

Ack

…

S:

sends

data

byte

N+X-

1

M:

Not

Ac-

knowl-

edge

M:

Stop

bit

13-0015