User's Manual

February 2017
DocID0xxxxx Rev 0.xx 15/27
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change
without notice. ww w.st.com
Special features are enabled by the following pins:
- STAT_LED (pin TP10): output to drive an external LED and indicated status of SPSGPE
connections. If this pin is used as output to an external LED, possible outputs are listed in
Table 11.
LED Output
Description
Periodic single flashing with long
ON time and short OFF time.
Application is waiting for commands from DTE.
Periodic single flashing with short
ON time and long OFF time.
Application has started and SPSGPE is seeking for
connection.
Periodic fast double flashing.
Application has started and SPSGPE is connected to
a gateway.
Table 11. Outputs to external LED by pin STAT_LED (TP10).
- RESET (pin TP6): internal pulled-up signal for resetting SPSGPE. It has to be tied low for at
least 100 ms and then released to perform SPSGPE unconditional hardware restart. Please
notice that unconditional hardware restart must not be used during normal device operation,
since it does not detach the device from the network. It shall be kept as emergency exit
procedure in the rare case the module gets stacked waiting for network response. It is
suggested to implement unconditional hardware restart (through a GPIO of the host
microcontroller unit, to be configured as open drain or through a push button) on SPSGPE
applications only as emergency exit procedure.
- ON/OFF (pin TP33): it performs the turning on/off procedure for SPSGPE when voltage
supply at VDD (pin 27) stands within recommended operating range (please refer to Table 1).
To start the turning off procedure when the module is turned on, the ON/OFF signal needs to
be tied low for at least 2 seconds. Similarly, to start the turning on procedure when the module
is turned off, the ON/OFF signal needs to be tied low for at least 2 seconds. The turning on/off
procedure can also be performed via AT commands (please refer to SPSGPE software
guide).
- PWR_MON (pin TP14): output signal indicating SPSGPE power status. It climbs high when
SPSGPE is properly powered on, and it climbs down when SPSGPE is not powered.
- USB_DEV_CONN (pin TP11): input signal to detect USB cable connections. It has to be high
when USB is connected, and low when USB is disconnected. Considering a 5 V tolerant pin, it
is recommended to connect it to the VBUS pin of USB connector with proper protection and
filtering network, adopting components like diode, ferrite bead and capacitors. If USB is used,
UART interface to DTE is automatically disabled. To re-enable UART, this pin has to be tied
low.