Chengdu Ebyte Electronic Technology Co.,Ltd
E31-400M17S User Manual
Copyright ©2012–2019
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Chengdu Ebyte Electronic Technology Co.,Ltd
6
17
SPI-MOSI
I
SPI data input pin; (see AX5243 manual for details)
18
SPI-CLK
I
SPI clock input pin; (see AX5243 manual for details)
19
SPI-NSS
I
Module chip select pin for starting an SPI communication; (see AX5243
manual for details)
20
GND
P
Ground wire, connected to the power reference ground
21
ANT
A
Antenna interface, stamp hole (50 ohm characteristic impedance)
22
GND
P
Ground wire, connected to the power reference ground
4 User Guide
4.1 Notice for Hardware
It is recommended to use DC stabilized power supply. The power supply ripple factor should be as small as possible, and
the module should be reliably grounded.
Please ensure that the positive and negative poles of the power supply are properly connected. If the reverse connection is
made, the module may be permanently damaged.
Please ensure the power supply voltage is within the working voltage range. If the maximum voltage is exceeded, the
module will be permanently damaged.
Please check the stability of the power supply, and the voltage cannot be fluctuated frequently;
When designing the power supply circuit for the module, it is recommended to reserve more than 30% of the margin to
achieve long-term stable operation of the system;
The installation location of the module should be as far away as possible from the power supply, transformers,
high-frequency wiring and other parts with large electromagnetic interference;
High-frequency digital routing, high-frequency analog routing, and power routing must avoid module locations. If the
wiring must pass under the module, assuming that the module is soldered to the Top Layer, the area where the module is in
contact with the Top Layer should be covered with copper (all copper is well grounded), and the area must be close to the digital
part of the module and routed in the Bottom Layer;
If the module is soldered or placed in the Top Layer, it is wrong to randomly route on the Bottom Layer or other layers,
which will affect the spurs and receiving sensitivity of the module to varying degrees;
If there is a device with large electromagnetic interference around the module, it will greatly affect the performance of the
module. It is recommended to maintain the distance from the module according to the strength of the interference. If
circumstances permit, it is recommended to do proper isolation and shielding;
If there are wirings with large electromagnetic interference around the module (such as high frequency digital, high
frequency analog, power line), the performance of the module will be greatly affected. It is recommended to do proper isolation
and shielding;
If the communication line uses 5V level, it must be connected in series with a 1k-5.1k resistor (not recommended, there is
still risk of damage);
Try to keep away from some physical layers as much as possible to avoid electromagnetic interference to other devices;
The antenna installation has a great influence on the performance of the module. Make sure that the antenna is exposed and
preferably vertical. When the module is installed inside the casing, it is recommended to use a good antenna extension cable to
extend the antenna to the outside of the casing;
The antenna must not be installed inside the metal case, which will greatly reduce the transmission distance.
