TMD27721 Datasheet, PDF (15/35 Pages) TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS – DIGITAL ALS and PROXIMITY MODULE

TMD2772
DIGITAL ALS
and PROXIMITY MODULE
TAOS147E − DECEMBER 2012
System State Machine Timing
The system state machine shown in Figure 5 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 Init, Prox
Accum, Prox Wait, and Prox ADC states. The Prox Init and Prox Wait times are a fixed 2.73 ms, 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 10. If an interrupt is generated as a result of the proximity cycle, it
lid ^{will be asserted at the end of the Prox ADC state and transition to the Sleep state if SAI is enabled.}
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
a _{WTIME. The formula to determine the wait time is given in the box associated with the Wait state in Figure 9.}
v ^{When the ALS feature is enabled (AEN), the state machine will transition through the ALS Init and ALS ADC}
states. The ALS Init state takes 2.73 ms, while the ALS ADC time is dependent on the integration time (ATIME).
ill ^{The formula to determine ALS ADC time is given in the associated box in Figure 9. If an interrupt is generated}
as a result of the ALS cycle, it will be asserted at the end of the ALS ADC state and transition to the Sleep state
if SAI is enabled.
G _st Prox
Sleep
A ^t _{Time: 2.73 ms}
Prox
Init
!PON
s _en ^PEN
I²C Start
INT & SAI
m ^{t PPULSE: 0 ~ 255 pulses}
Time: 16.0 μs/pulse
Range: 0 ~ 4.1 ms
a _{l con Time: 2.73 ms}
Prox
Accum
Prox
Wait
Idle
ALS
INT & SAI
ALS
ADC
!WEN &
!AEN
!AEN
!PEN & !WEN
& AEN
!PEN & WEN
& AEN
ALS
Init
ATIME: 1 ~ 256 steps
Time: 2.73 ms/step
Range: 2.73 ms ~ 699 ms
Time: 2.73 ms
a _{PTIME: 1 ~ 256 steps}
ic ^{Time: 2.73 ms/step}
Range: 2.73 ms ~ 699 ms
Prox
ADC
!WEN &
AEN
WEN
AEN
WTIME: 1 ~ 256 steps
n ^Wait
Time:
WLONG = 0
2.73 ms/step
WLONG = 1
32.8 ms/step
h Note: PON, PEN, WEN, AEN, and SAI are fields in the Enable register (0x00).
Range: 2.73 ms ~ 699 ms 32.8 ms ~ 8.39s
Tec ^{Figure 11. Detailed State Diagram}
Copyright E 2012, TAOS Inc.
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