6

FN7465.2

December 1, 2006

Command Register

The command register is used to define the ADC's

operations. Table 1 shows the primary commands used to

control the ADC.

Note that there are two classes of operating commands:

three for internal timing, and three for external (arbitrary)

timing.

When using any of the three internal timing commands, the

device self-times each conversion, which is nominally 110ms

When using any of the three external timing commands,

each command received by the device ends one conversion

and begins another. The integration time of the device is

the next. The integration time can be between 1ms and

100ms. The external timing commands can be used to

synchronize the ADC’s integrating time to a PWM dimming

frequency in a backlight system in order to eliminate noise.

TABLE 1. COMMAND REGISTERS AND FUNCTIONS

COMMAND

FUNCTION

8C(hex)

ADC is powered-down. To enable ADC from a powered-down state, send any command to the ISL29002.

0C(hex)

ADC is reset. A reset restarts the counter value to zero and returns the clock cycle to zero.

00(hex)

Internal Timing Mode. Integration

time is 110ms per photodiode.

04(hex)

08(hex)

30(hex)

External Timing Mode. Each external

timing command sent to the device

ends one integration period and

begins another.

34(hex)

38(hex)

1xxx_xxxx

(binary)

FIGURE 11A.

FIGURE 11B.

FIGURE 11.

Start

W

AA

A6

A5

A4

A3

A2

A1

A0

W

A

R7

R6

R5

R4

R3

R2

R1

R0

A

AA

12

345

678

912

34

567

89

STOP

SDA DRIVEN BY MASTER

POWER DOWN CMD 8C(h)

I

SDA DRIVEN BY MASTER

I

I

DEVICE ADDRESS 40(h) to 47(h)

I

Start

A

A

A6

A5

A4

A3

A2

A1

A0

R

A

A

A

A

D7

D6

D5

D4

D3

D2

D1

D0

A

D7

D6

D5

D4

D3

D2

D1

D0

A

12

345

678

912

345

678

912

34

567

89

I

SDA DRIVEN BY MASTER

R/W

SDA DRIVEN BY ISL29002

I

I

DEVICE ADDRESS 44(HEX)

I

MSB OF SENSOR READING

STOP

LSB OF SENSOR READING

SDA DRIVEN BY ISL29002

ISL29002