MLX16305 Datasheet, PDF (23/29 Pages) Melexis Microelectronic Systems – Interlock switch sensor interface IC

MLX16305
Interlock switch sensor interface IC
15. Multiplexing the ADC input by setting MEAS_OUT High Impedant
By applying the correct sequence on the digital input pins the MEAS_OUT pin can be set high impedant.
This is of interest when using 2 or more MLX16305 in parallel for applications with more than 6 switches
to be monitored. The MLX16305 devices are then multiplexed on the same ADC input channel.
The AD input from the microcontroller can be shared by multiple MLX16305 devices in parallel.
With 1 extra digital IO serving as ENABLE for a second device, 6more channels can be controlled.
Procedure:
• First while ENABLE2=0, set MUX_SENSE[0:2] = 000b
• Then latch this value by setting ENABLE2 = 1
• From now on MEASOUT2 is high impedant, and regardless the values of VI_CTRL or
MUX_SENSE[0:2], this remains.
• Switching from device one to device two is done by setting MUX_SENSE[0:2] = 000b while
ENABLE1=0. Setting ENABLE1=1 makes MEASOUT1 high impedant.
• Now ENABLE2 can be reset to 0 without possible conflict between the 2 MEASOUT outputs.
KL15 / IG N
VSUP
ADC
VREF
MEAS_OUT
ENABLE1
VI_C TR L
MUX_SENSE0
MUX_SENSE1
MUX_SENSE2
M icroctrl _ENABLE2
Sense1
Sense2
Sense3
M LX16305 Sense4
Sense5
Sense6
R ref
Sense1
Sense2
Sense3
M LX16305 Sense4
Sense5
Sense6
R ref
3901016305
Rev. 005
Page 23 of 29
Data Sheet
Oct/06