TSL2550 View Datasheet(PDF) - Unspecified

Part Name

Description

Manufacturer

TSL2550

AMBIENT LIGHT SENSOR WITH SMBus INTERFACE

Unspecified 

TSL2550

AMBIENT LIGHT SENSOR

WITH SMBus INTERFACE

TAOS029 – SEPTEMBER 2002

Command Register

The command register contains eight bits as described in Table 1 and defaults to 0 (0x00) at power-up. A

command summary appears in Table 2.

B7

RSEL2

Table 1. Command Register Data Format

RSEL

B6

RSEL1

B5

RSEL0

RESERVED

B4

B3

B2

0

0

0

ADCEN

B1

ADCEN

PON

B0

PON

FIELD

RSEL

RESERVED

ADCEN

PON

BITS

7 to 5

4 to 2

1

0

DESCRIPTION

Read Data Select. This field determines the data output by the TSL2550

during read.

Field Value

Read Value

000

Command register

010

ADC channel 0

100

ADC channel 1

Reserved for factory test. These bits should always be written to 0.

ADC Enable. This field actives the ADC. Writing a 1 activates the ADC.

Writing a 0 disables the ADC. ADCEN is normally used in conjunction with

PON.

Note: Both ADCEN and PON must be asserted before the ADC channels will

operate correctly.

Power ON. This field activates the internal oscillator to permit the timers and

ADC channels to operate. Writing a 1 activates the oscillator. Writing a 0

disables the oscillator. PON is normally used in conjunction with ADCEN.

Note: For the Duration of writes and reads over the SMB interface, this bit is

overridden and the oscillator is enabled, independent of the state of PON.

Note: Both ADCEN and PON must be asserted before the ADC channels will

operate correctly.

The command register is used primarily to select which register will be read during a read cycle (RSEL) and

to control the power consumption of the device (ADCEN and PON). When ADCEN and PON are high, the device

is in the full powered-up state and is fully operational. When ADCEN and PON are low, both the ADC and the

internal oscillator are powered down, resulting in minimum power consumption. Both ADCEN and PON should

always be asserted and de-asserted together. The remaining bits (B4, B3, and B2) in the command register

should always be written 0. For details on using the command register, see the Operation section, below.

COMMAND

00h

03h

43h

83h

Table 2. Command Summary

FUNCTION

Place device in power-down state

Read command register

Read ADC Channel 0

Read ADC Channel 1

Copyright E 2002, TAOS Inc.

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The LUMENOLOGYr Company

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