TMD26721 datasheet(9/29 Pages) TAOS

9 / 29 page

TMD2672

DIGITAL PROXIMITY DETECTOR

TAOS149C − AUGUST 2012

E 2012, TAOS Inc.

The LUMENOLOGY

r Company

www.taosinc.com

PRINCIPLES OF OPERATION

System State Machine

An internal state machine provides system control of the proximity detection and power management features

of the device. At power up, an internal power-on-reset initializes the device and puts it in a low-power Sleep

state.

When a start condition is detected on the I2C bus, the device transitions to the Idle state where it checks the

Enable register (0x00) PON bit. If PON is disabled, the device will return to the Sleep state to save power.

Otherwise, the device will remain in the Idle state until a proximity function is enabled. Once enabled, the device

will execute the Prox and Wait states in sequence as indicated in Figure 6. Upon completion and return to Idle,

the device will automatically begin a new prox-wait cycle as long as PON and PEN are enabled.

If the Prox function generates an interrupt and the Sleep-After-Interrupt (SAI) feature is enabled the device will

transition to the Sleep state and remain in a low-power mode until an I2C command is received. See the

Interrupts section for additional information.

!PEN &

WEN

!WEN

PEN

Sleep

Idle

Wait

Prox

I2C

Start

!PON

INT & SAI

WEN

Figure 6. Simplified State Diagram

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