UC-00-M15 EN R1.4
Hardware Design
18
4.2.3
Active Antenna State Detection
UM220-IV L module can detect the active antenna state including open-circuit, short-
circuit and normal state. The host computer enables or disables the antenna state
detection function by transmitting commands via serial ports, and receives the detected
antenna state via serial ports. The module cuts off the power supply automatically when
detecting the short-circuit state of antenna.
1)
Antenna Short-circuit Detection
If the antenna short-circuit detection function is required, connect the antenna power
supply to the module's V_ANT Pin after cascading an appropriate value of resistance,
and feed the antenna through the internal switch. If the V_ANT pin is directly connected
without a serial resistor, the module will be damaged when the antenna is short-
circuited. The internal switch is turned off by default, which can be switched with the
CFGANT command.
When the module detects an antenna short-circuit, the antenna feed is cut off
immediately through the internal switch, periodically feeds the antenna and detects the
state. Use ANTSTAT for the query.
If the working voltage of the antenna is 3.3V, the 3.3V power supply (VCC_RF) provided
by the module can be connected in series with a 10Ω resistor to the V_ANT pin, and turn
on the internal switch through CFGANT to power the antenna. If an antenna short circuit
is detected at this time, the module will automatically turn off the switch. When there is
a need to save the power consumption, turn off the switch through CFGANT.
Refer to
UM220-IV L_
Protocol Specification
for more details
