MLX75030 Datasheet, PDF (58/72 Pages) Melexis Microelectronic Systems – Universal ActiveLight Sensor Interface

MLX75030 Universal ActiveLight Sensor Interface
Datasheet
t_{wdt_closed}
t_{wdt_open}
WatchdogWindow ^{High = Active Window}
t_{wdt_open}
WT (Watchdog Trigger)
Missing WT
MR (Master Reset)
Initial Period
t_{wdt_init}
t_{wdt_closed}
t_{wdt_open}
t ms
WatchdogWindow _{High = Active Window}
WT (Watchdog Trigger)
Premature WT
MR (Master Reset)
Initial Period
t_{wdt_init}
t ms
Figure 17 : Functionality of the window watchdog timer
A reset of the µC due to time-out of the watchdog is achieved by setting the MR pin low during a time t_MR (default state of
the MR pin is high).
When the device is operating in Sleep or Standby Mode, the WAKE_UP pin will be monitored. When a falling edge is
detected on that pin, the device will switch to Normal Running Mode and, when waking up from Sleep Mode, the Watchdog
Timer will be started (with an initial window time of t_{wdt_init}).
Note that no pull-up or pull-down resistor is foreseen on the WAKE_UP pin. To avoid that parasitic spikes can wake up the
device, the WAKE_UP input is debounced (typical debounce time is in the range of 2µs). The low time on the WAKE_UP pin
should be at least a time t_{wu_l}.
REVISION 005 – DECEMBER 2013
3901075030
PAGE 58 OF 72