MLX75031 Datasheet, PDF (56/67 Pages) Melexis Microelectronic Systems – Optical Gesture & Proximity Sensing IC

MLX75031
Optical Gesture & Proximity Sensing IC
with Integrated LED Drivers
Datasheet
G_ADJ_LED1 G_ADJ_LED0
Gain
0
0
0.99
0
1
1.98
1
0
2.98
1
1
3.99
SetPLS<3:2>: not implemented, read as '0'
Rise<1:0>: controls the shape of the Active Light pulses
Rise1 Rise0
0
0
0
1
1
0
1
1
Rise time of Active Light
pulses
(1tau - µs)
7
5
3
1
8.14. Window Watchdog Timer
The internal watchdog timer is a watchdog based on two different windows: an open and a closed window.
During the open window the master can restart the watchdog timer. During the closed window, no restarts
are accepted.
The restart (re-initialisation) of the watchdog timer happens via WatchDog Trigger Command: when a WDT
command is sent, the watchdog will be restarted.
After a POR or a reset issued by the watchdog and after a wake-up from Sleep Mode (by uploading the NRM
command), the window watchdog will open an active window of a time twdt_init, during which a watchdog
restart must be issued by the µC. If no watchdog restart is received by the end of the open window, the µC
will be reset.
After this initial period, the window watchdog is programmed to wait a time twdt_closed during which no
watchdog restarts are allowed. If a watchdog restart is sent during the closed window time, the watchdog
will reset the master via the MR (Master Reset) pin.
After a closed window, an open window of a time twdt_open will follow during which a watchdog restart is
expected. If no watchdog restart is received till the end of the open window, the µC will be reset via the MR
pin.
Changing mode between Normal Running Mode and Standby Mode will not influence the watchdog timing
or state. Also a CR command will not change the used window times. The watchdog counter will not be
influenced when changing mode between NRM and STBY or when uploading a CR command.
The Watch Dog Timer is disabled in Sleep Mode. Sending a WDT command in the Sleep Mode will set the
Previous Command Invalid flag high. Coming back from Sleep Mode to Normal Running Mode always
restarts the watchdog with the initial timing window.
This figure shows what timing windows are used in the different operating modes :
REVISION 001 – JANUARY, 2013
39010xxxxx
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