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User Manual May 2019 | Page 33/49
USER MANUAL
Scavenger Transmitter Module
STM 330 / STM 331 STM 331U / STM 332U / STM 333U
(Stepcode DE and later)
4
APPLICATIONS INFORMATION
4.1
Using the WAKE pins
The logic input circuits of the WAKE0 and WAKE1 pins are supplied by UVDD and therefore
also usable in “Deep Sleep Mode”. Due to current minimization there is no internal pull-up
or pull-down at the WAKE pins. When STM 33x is in “Deep Sleep Mode” and the logic levels
of WAKE0 and / or WAKE1 is changed, STM 33x starts up.
As the there is no internal pull-up or pull-down at the WAKE0 pin, it has to be en-
sured by external circuitry, that the WAKE0 pin is at a defined logic level at any
time. At time of delivery a jumper is connected between WAKE0 and UVDDext.
WAKE1 provides an internal 1.8 MΩ pull-up. See figure below.
When the LRN button is pressed WAKE1 is pulled to GND and a teach-in telegram is trans-
mitted or mode change is executed. As long as the button is pressed a small current of ap-
proximately 1 µA is flowing. It is possible to connect an additional external button in paral-
lel between WAKE1 and GND if a different position of the button in the device is required.
WAKE0 is connected to UVDDext via a jumper at time of delivery. If the module is mounted
onto a host PCB the jumper has to be removed. The circuitry on the host PCB then has to
ensure that WAKE0 is always in a defined position.
There are two ways to use WAKE0:
Connect WAKE0 to UVDDext and connect an external button between WAKE0 and GND.
As long as the button is pressed a current of 1 µA will flow.
Connect a 3 terminal switch and switch WAKE0 to either GND or UVDDext. In this case
there is no continuous flow of current in either position of the switch.
EO3000I
W
A
KE
0
W
A
KE
1
U
V
D
D
UVDDext
STM 33x
WAKE1
WAKE0
GND
1M8
1M8
LRN Button
Jumper installed at
time of delivery
