ZOPT2201 Datasheet

© 2016 Integrated Device Technology, Inc

18

September 2, 2016

3.5

Conversion Control State Machine

3.5.1

Start Up after Power-On or Software Reset

The main state machine is set to “Start State” during a power-on or software reset. As soon as the reset is released, the internal oscillator is

started and the programmed I²C address and the trim values are read from the internal NVM trimming data block. The ZOPT2201 enters

Standby Mode as soon as the Idle State is reached (see Figure 3.3).

NOTE: If the I²C address has not yet been read, the device will respond with NACK to any I²C command and ignore any request to avoid

responding to an incorrect I²C address.

If any of the sensor operation modes becomes activated through an I²C command (i.e., the LS_EN bit is set to 1 and the sensor mode is

selected with the respective bits in the MAIN_CTRL register), the internal support blocks are immediately powered on. Once the voltages and

currents are settled (typical after 500µs), the state machine checks for trigger events from a measurement scheduler to start conversions

according to the selected measurement repeat rates (see section 3.11.2).

When the user resets the LS_EN bit to 0, a running conversion will be completed and the relevant ADCs and support blocks will move to

Standby Mode thereafter.

Figure 3.3 Main State Machine

Run

POR

Standby

LS

conversion

Wait for repeat

LS_MEAS_RATE

LS_EN

LS_EN

!LS_EN

LS inactive

Start oscillator

!LS_EN

Start oscillator

Stop oscillator

Run

Read out

NVM fuses

LS is either ALS or

UVBS depending

on the LS_Mode bit