MLX75031 Datasheet, PDF (33/67 Pages) Melexis Microelectronic Systems – Optical Gesture & Proximity Sensing IC

MLX75031
Optical Gesture & Proximity Sensing IC
with Integrated LED Drivers
Datasheet
Table 16 : Basic Measurement Execution Times tdr
Measurement Type
Min. tdr
(µs)
Max. tdr
(µs)
Measurement Sequence 1
520
611
Measurement Sequence 2: measure one Active Light channel with
typical Tdc_pulse<1:0> and typical TP<2:0> settings
786
924
Measurement Sequence 2: measure one Active Light channel with
maximum Tdc_pulse<1:0> and maximum TP<2:0> settings
1024
1203
Measurement Sequence 2: measure two Active Light channels with
typical Tdc_pulse<1:0> and typical TP<2:0> settings
921
1082
Measurement Sequence 2: measure two Active Light channels with
maximum Tdc_pulse<1:0> and maximum TP<2:0> settings
1159
1361
Note : the DR pin can be used as an interrupt for the master device as it indicates when a read-out cycle can
be started.
CS
SCLK
MOSI
MISO
Tri state
SM/SD Command
tcs_dr
Status Flags/Ctrl 1
tdr
Tri state
DR
Internal State
Idle State
Measurement Cycle SM/SD
Idle State
Figure 11 : Timing Diagram of a Measurement Cycle
The SM command contains 2 option bits: R0 & T. The bit R0 sets the polarity of the ADC input buffer in
Active Light channels A & B. The bit T provides test pulses during the Active Light measurements.
• R0: Inversion of the offset of the ADC_buffer. The output will change from (Signal +
Offset_opamp_buf) to (Signal - offset_opamp_buf). In this way, by processing 2 measurements with
inverted R0 bits, the offset of the ADC buffer filter can be cancelled.
• T: This bit replaces the light pulses by internal current pulses during the Active Light measurements.
The LED driver will not be activated when this option bit is selected.
The SM command contains an option bit T. If this bit is set to 0, normal Active Light measurements are
performed (i.e. the external LED's are fired and the Active Light channels A and/or B are measured). If this
bit is set to 1, no LED's are fired, but an internal test pulse is applied to channels A and/or B. The internal
test pulse can be influenced in amplitude by the bits DACA7 and DACA6 (when LED A is fired) or by the bits
DACB7 and DACB6 (when LED B is fired).
DACA7/
DACB7
0
0
1
1
DACA6/
DACB6
0
I_Testpulse [uA]
5
Typical ADC value [LSB] at
default TP & Gain settings
8466
1
13
14737
0
21
20967
1
29
27195
Table 17 : Current levels for Active Light testmode.
REVISION 001 – JANUARY, 2013
39010xxxxx
Page 33 of 33