User's Manual

February 2017
DocID0xxxxx Rev 0.xx 12/27
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
3 Hardware design
3.1 Pin usage
If used with default firmware and interfaced to a host microcontroller unit, SPSGPE requires minimum
power, ground and UART to transmit and receive signals, that is to be connected. Other signals are
optional and provide additional functionality. Unused signals must be left unconnected.
In case the module is connected to a host microcontroller unit, SPSGPE pins requiring connections are
outlined in Table 9.
Pin
Name
Description
Optional
TP27
VDD
Supply input voltage
No
TP17
GND
Ground
No
TP44
TP46
TP21
UART2_TX
Serial data output to DTE
No
TP20
UART2_RX
Serial data input from DTE
No
TP18
USB_P /
RTS
Request to send signal from DTE, if used.
If flow controls are not used, this pin must be connected to
GND.
It could be left floating, if USB is supported by firmware.
Yes
TP33
ON/OFF
Input for switching ON or OFF the module
(1)
(toggle command)
Yes
TP6
RESET
Reset input, active low, internal pull-up
(1)
No
TP45
ANT
Connection pin for external antenna (50 Ω)
No
(1) Open drain connection is required.
Table 9. SPSGPE pins requiring connections, when the module is connected to a host
microcontroller unit.
In another typical application circuit, SPSGPE is connected to a host computer through a standard USB
connector. In this case, module pins requiring connections are listed in Table 10.
Pin
Name
Description
Optional
TP27
VDD
Supply input voltage
No
TP17
GND
Ground
No
TP44
TP46
TP18
USB_P / RTS
USB Data– (90 Ω differential)
No
TP19
USB_N / CTS
USB Data+ (90 Ω differential)
No
TP11
USB_DEV_CO
NN
Input for detecting the connection to the USB cable.
Pull it high when USB cable is connected.
No
TP33
ON/OFF
Input for switching module ON or OFF
(toggle command)
Yes
TP6
RESET
Reset input, active low, internal pull-up
No
TP45
ANT
Connection pin for external antenna (50 Ω)
No
Table 10. SPSGPE pins requiring connections, when the module is connected to a host computer
via USB.