4

ICS94236

0451A

—01/10/03

1.

The ICS clock generator is a slave/receiver, I

for verification. Readback will support standard SMBUS controller protocol. The number of bytes to

readback is defined by writing to byte 8.

2.

When writing to byte 11 - 12, and byte 13 - 14, they must be written as a set.

If for example, only byte

14 is written but not 15, neither byte 14 or 15 will load into the receiver.

3.

The data transfer rate supported by this clock generator is 100K bits/sec or less (standard mode)

4.

The input is operating at 3.3V logic levels.

5.

The data byte format is 8 bit bytes.

6.

To simplify the clock generator I

controller. The bytes must be accessed in sequential order from lowest to highest byte with the ability to

stop after any complete byte has been transferred. The Command code and Byte count shown above must

be sent, but the data is ignored for those two bytes. The data is loaded until a Stop sequence is issued.

7.

At power-on, all registers are set to a default condition, as shown.

Notes:

Brief I

Programmable System Frequency Generator

Register Name

Byte

Description

PWD Default

Functionality & Frequency

Select Register

0

Output frequency, hardware / I

2

C

frequency select, spread spectrum &

output enable control register.

See individual

byte description

Output Control Registers

1-6

Active / inactive output control

registers/latch inputs read back.

See individual

byte description

Vendor ID & Revision ID

Registers

7

Byte 11 bit[7:4] is ICS vendor id - 1001.

Other bits in this register designate device

revision ID of this part.

See individual

byte description

Byte Count

Read Back Register

8

Writing to this register will configure

byte count and how many byte will be

Watchdog Timer

Count Register

9

Writing to this register will configure the

number of seconds for the watchdog

timer to reset.

Watchdog Control Registers 10 Bit [6:0]

Watchdog enable, watchdog status and

programmable 'safe' frequency' can be

configured in this register.

000,0000

VCO Control Selection Bit

10 Bit [7]

This bit select whether the output

frequency is control by hardware/byte 0

configurations or byte 11&12

programming.

0

VCO Frequency Control

Registers

11-12

These registers control the dividers ratio

into the phase detector and thus control

the VCO output frequency.

Depended on

hardware/byte 0

configuration

Spread Spectrum Control

Registers

13-14

These registers control the spread

percentage amount.

Depended on

hardware/byte 0

configuration

Group Skews Control

Registers

15-16

Increment or decrement the group skew

amount as compared to the initial skew.

See individual

byte description

Output Rise/Fall Time

Select Registers

17-20

These registers will control the output

rise and fall time.

See individual

byte description