TCS37727 datasheet(21/50 Pages) AMSCO

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[v1-01] 2018-Mar-14

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TCS3772 − Principles of Operation

System Timing

The system state machine shown in Figure 22 provides an

overview of the states and state transitions that provide system

control of the device. This section highlights the programmable

features, which affect the state machine cycle time, and

provides details to determine system level timing.

When the proximity detection feature is enabled (PEN), the

state machine transitions through the Prox Accum, Prox Wait,

and Prox ADC states. The Prox Wait time is a fixed 2.4ms,

whereas the Prox Accum time is determined by the number of

proximity LED pulses (PPULSE) and the Prox ADC time is

determined by the integration time (PTIME). The formulas to

determine the Prox Accum and Prox ADC times are given in the

associated boxes in Figure 27. If an interrupt is generated as a

result of the proximity cycle, it will be asserted at the end of the

Prox ADC state.

When the power management feature is enabled (WEN), the

state machine will transition in turn to the Wait state. The wait

time is determined by WLONG, which extends normal operation

by 12× when asserted, and WTIME. The formula to determine

the wait time is given in the box associated with the Wait state

in Figure 27.

When the RGBC feature is enabled (AEN), the state machine will

transition through the RGBC Init and RGBC ADC states. The

RGBC Init state takes 2.4 ms, while the RGBC ADC time is

dependent on the integration time (ATIME). The formula to

determine RGBC ADC time is given in the associated box in

Figure 27. If an interrupt is generated as a result of the RGBC

cycle, it will be asserted at the end of the RGBC ADC.

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