TOBY-R2 series - System integration manual
UBX-16010572 - R10
System description
Page 34 of 151
1.7.2
Antenna detection interface (ANT_DET)
The antenna detection is based on ADC measurement. The ANT_DET pin is an Analog to Digital
Converter (ADC) provided to sense the antenna presence.
The antenna detection function provided by ANT_DET pin is an optional feature that can be
implemented if the application requires it. The antenna detection is forced by the +UANTR AT
command. See the u-blox AT commands manual
for more details on this feature.
The ANT_DET pin generates a DC current (for detailed characteristics see the TOBY-R2 series data
sheet
) and measures the resulting DC voltage, thus determining the resistance from the antenna
connector provided on the application board to GND. So, the requirements to achieve antenna
detection functionality are the following:
an RF antenna assembly with a built-in resistor (diagnostic circuit) must be used
an antenna detection circuit must be implemented on the application board
See section
for antenna detection circuit on application board and diagnostic circuit on antenna
assembly design-in guidelines.
1.8
SIM interface
1.8.1
SIM interface
TOBY-R2 series modules provide high-speed SIM/ME interface including automatic detection and
configuration of the voltage required by the connected SIM card or chip.
Both 1.8 V and 3 V SIM types are supported. Activation and deactivation with automatic voltage
switch from 1.8 V to 3 V are implemented, according to ISO-IEC 7816-3 specifications. The VSIM
supply output provides internal short circuit protection to limit start-up current and protect the SIM
to short circuits.
The SIM driver supports the PPS (Protocol and Parameter Selection) procedure for baud-rate
selection, according to the values determined by the SIM card or chip.
1.8.2
SIM detection interface
The GPIO5 pin is by default configured to detect the external SIM card mechanical / physical presence.
The pin is configured as input, and it can sense SIM card presence as intended to be properly
connected to the mechanical switch of a SIM card holder as described in section
Low logic level at GPIO5 input pin is recognized as SIM card not present
High logic level at GPIO5 input pin is recognized as SIM card present
The SIM card detection function provided by GPIO5 pin is an optional feature that can be implemented
/ used or not according to the application requirements: an Unsolicited Result Code (URC) is generated
each time that there is a change of status (for more details see u-blox AT commands manual
+UGPIOC, +CIND, +CMER).
The optional function “SIM card hot insertion/removal” can be additionally configured on the GPIO5
pin by specific AT command (see the u-blox AT commands manual
, +UDCONF=50), in order to
enable / disable the SIM interface upon detection of external SIM card physical insertion / removal.
