Chengdu Ebyte Electronic Technology Co., Ltd.
E22-900M30S User manual
Copyright ©2012–2018, Chengdu Ebyte Electronic Technology Co.,Ltd.
5
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The module should be as far away as possible from the power supply, transformers, high-frequency wiring and other
parts with large electromagnetic interference.
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High-frequency digital traces, high-frequency analog traces, and power traces must be avoided under the module. If
it is necessary to pass through the module, assume that the module is soldered to the Top Layer, and the copper is
spread on the Top Layer of the module contact part(All copper-covered and well grounded), and must be close to the
digital part of the module and routed in the Bottom Layer.
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Assuming the module is soldered or placed in the Top Layer, it is also wrong to randomly route the Bottom Layer or
other layers, which will affect the module's spurs and receiving sensitivity to varying degrees.
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Assume that there are traces with large electromagnetic interference around the module (high-frequency digital, high-
frequency analog, power trace), which will greatly affect the performance of the module. It is recommended to stay
away from the module according to the strength of the interference. If necessary, appropriate isolation and shielding
can be done;
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If the communication line uses a 5V level, a 1k-5.1k resistor must be connected in series (not recommended, there is
still a risk of damage).
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Try to stay away from some physical layers and also have a 2.4GHz TTL protocol, for example: USB3.0
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The antenna mounting structure has a great influence on the performance of the module. It is necessary to ensure that
the antenna is exposed, preferably vertically upward. When the module is mounted inside the case, use a good antenna
extension cable to extend the antenna to the outside of the case.
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The antenna must not be installed inside the metal case, which will greatly reduce the transmission distance.
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It is recommended to add a 200R protection resistor to the RXD/TXD of the external MCU.
4.2 Software Programming
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This module is SX1268/PA+LNA. Its driving mode is exactly the same as SX1268/SX1262. Users can
operate according to SX1268/SX1262 chip datasheet.
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DIO1 and DIO2 are general-purpose IO ports, which can be configured into multiple functions. DIO2 can be
connected to TXEN and not connected to the MCU's IO port. It can be used to control the RF switch transmission. If
not used, you can hang it. For details, see the SX1262 manual.
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DIO 3 is used to supply 32 MHz TCXO crystal oscillator.
