User Manual

USER MANUAL V1.05

STM 330 / STM 331 / STM 330C / STM 332U / STM 333U

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.

EO3000I

WAKE0

WAKE1

UVDD

UVDDext

STM 33x

WAKE1

WAKE0

GND

1M8

LRN Button

Jum per installed at

time of delivery

When the LRN button is pressed WAKE1 is pulled to GND and a teach-in telegram is trans-

mitted. As long as the button is pressed a small current of approximately 1 µA is flowing. It

is possible to connect an additional external button in parallel 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.