TMD2671

DIGITAL PROXIMITY DETECTOR

TAOS144B − SEPTEMBER 2012

12

r

r

Copyright

E 2012, TAOS Inc.

The LUMENOLOGY

r Company

www.taosinc.com

State Diagram

The following state diagram shows a more detailed flow for the state machine. The device starts in the sleep

mode. The PON bit is written to enable the device. A 2.72-ms Start Delay will occur before entering the start

state. If the PEN bit is set, the state machine will step through the proximity accumulate, then proximity ADC

conversion states. As soon as the conversion is complete, the state machine will move to the Wait Check state.

If the WEN bit is set, the state machine will then cycle through the wait state. If the WLONG bit is set, the wait

cycles are extended by 12

move to the 2.72-ms Wait Delay state before returning to the Start state.

1 to 256 steps

Step: 2.72 ms

Time: 2.72 ms − 696 ms

Recommended − 2.72 ms 1023 Counts

PEN = 0

Prox

Check

PON = 1

PON = 0

Sleep

Wait

Check

Start

Wait

WEN = 1

Prox

Accum

Prox

ADC

Wait

Delay

PEN = 1

1 to 255 LED Pulses

Pulse Frequency: 62.5 kHz

Time: 16.3

ms − 4.2 ms

WLONG = 0

1 to 256 steps

Step: 2.72 ms

Time: 2.72 ms − 696 ms

WLONG = 1

1 to 256 steps

Step: 32.6 ms

Time: 32.6 ms − 8.35 s

5.44 ms

WEN = 0

Start

Delay

2.72 ms

Figure 9. Expanded State Diagram