UNICORECOMM UM220-IV M0, Инструкция по установке и эксплуатации

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7
No Name I/O Electrical level Description
6 V_BCKP I 1.4V~3.6V Voltage for RTC
7 VCC_IO I 2.8V~3.6V GPIO power supply
8 VCC I 2.8V~3.6V Main power
9 nRESET I LVTTL
For reset, Low level active, if you do not
use the pin, please leave it hanging
10 GND I Ground
11 RF_IN I GNSS signal input (BDS B1+GPS L1
）
12 GND I Ground
13 NC O Reserve
14 VCC_RF
2
O =VCC Output voltage RF section
15 NC I/O Reserve
16 NC I/O Reserve
17 NC I/O Reserve
18 NC I/O Reserve
4 Hardware Design
4.1 Design in Considerations
To make UM220-IV M0 to work properly, you need to properly connect the following
:
The Module VCC has good monotonicity. If the VCC power off and then on, the power
off time must be more than 10ms.
 Recommended in serial concatenated RX place 1KΩ resistance, TX concatenated
33Ω or 1 KΩ resistance, other need PIO concatenated 4.7K resistor in the Pin
.

Connect all the GND pins to ground
.
 Connect the RF_IN signal to the antenna, and the line will keep 50Ω impedance
matching
.
 Ensure COM1 is connected to a PC or an external processor, users can use this
serial port to receive position data. COM1 is also necessary for firmware upgrades.
In order to obtain good performance, special concern should be paid during the design :

Power supply: Stable and low ripple power is necessary for good performance.
Make sure the peak to peak voltage ripple does not exceed 50mV.
− Using LDO to ensure the purity of power supply
2 VCC_RF does not have short circuit detection function;