SI1141(2011) View Datasheet(PDF) - Silicon Laboratories

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SI1141
(Rev.:2011)

PROXIMITY/AMBIENT LIGHT SENSOR IC WITH I2C INTERFACE

Silicon Laboratories 

Si1141/42/43

4.2. Command Protocol

The I2C map implements a bidirectional message box between the host and the Si1141/42/43 Sequencer. Host-

writable I2C registers facilitate host-to-Si1141/42/43 communication, while read-only I2C registers are used for

Si1141/42/43-to-host communication.

Unlike the other host-writable I2C registers, the COMMAND register causes the internal sequencer to wake up

from Standby mode to process the host request.

When a command is executed, the RESPONSE register is updated. Typically, when there is no error, the upper

four bits are zeroes. To allow command tracking, the lower four bits implement a 4-bit circular counter. In general, if

the upper nibble of the RESPONSE register is non-zero, this indicates an error or the need for special processing.

The PARAM_WR and PARAM_RD registers are additional mailbox registers.

In addition to the registers in the I2C map, there are environmental parameters accessible through the Command/

Response interface. These parameters are stored in the internal ram space. These parameters generally take

more I2C accesses to read and write. The Parameter RAM is described in "4.6. Parameter RAM" on page 45.

Table 5. Command Register Summary

COMMAND Register

PARAM_W PARAM_RD

Error Code in

Name

Encoding R Register Register RESPONSE Register

Description

PARAM_QUERY 100 aaaaa

—

nnnn nnnn

PARAM_SET 101 aaaaa dddd dddd nnnn nnnn

PARAM_AND 110 aaaaa dddd dddd nnnn nnnn

PARAM_OR 111 aaaaa dddd dddd nnnn nnnn

NOP

000 00000

—

—

RESET

000 00001

—

—

BUSADDR 000 00010

—

—

Reads the parameter pointed to by bit-



field [4:0] and writes value to

PARAM_RD.

See Table 10 for parameters.

Sets parameter pointed by bitfield [4:0]



with value in PARAM_WR, and writes

value out to PARAM_RD. See Table 10

for parameters.

Performs a bit-wise AND between

PARAM_WR and Parameter pointed by



bitfield [4:0], writes updated value to

PARAM_RD.

See Table 10 for parameters.

Performs a bit-wise OR of PARAM_WR



and parameter pointed by bitfield [4:0],

writes updated value to PARAM_RD.

See Table 10 for parameters.



Forces a zero into the RESPONSE

register



Performs a software reset of the

firmware

—

Modifies I2C address

Reserved

000 00011

—

—

—

—

Reserved

000 00100

—

—

PS_FORCE 000 00101

—

—

ALS_FORCE 000 00110

—

—

—

—



Forces a single PS measurement



Forces a single ALS measurement

PSALS_FORCE 000 00111

—

—



Forces a single PS and ALS

measurement

Preliminary Rev. 0.5

17

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