# STM32WL55 LORA Ping pong example

<img src="./asset/STM32WL55_Board.jpg">

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This is an example of LORA communication between STM32WL55 cards, and the frequency band of 868 ~ 928Mhz is used.
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Long-distance wireless communication of up to 30Km is possible, and it has advantages in space, low power, and price compared to the structure that generally uses SX1276 + separate MCU.
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Related hardware kits can be purchased from the Naver Smart Store.
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[Purchase Link : naver smart store](https://smartstore.naver.com/axden)

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You can purchase it by contacting sales@axden.io

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### STM32WL55 LORA Ping pong terminal
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baudrate : 9600
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<table>
<tr align="center">
  <td>TX</td>
</tr>
  <tr align="center">
    <td><img src="./asset/STM32WL55_TX.png"></td>
  </tr>
</table>

<table>
<tr align="center">
  <td>RX</td>
</tr>
  <tr align="center">
    <td><img src="./asset/STM32WL55_RX.png"></td>
  </tr>
</table>

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### STM32WL55 Radio setup

<img src="./asset/Radio_setup_path.png">
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SubGHZ-Phy / App / subghz_phy_app.c

```
#define REGION_AS923

#if defined( REGION_AS923 )

#define RF_FREQUENCY                                923000000 // Hz

#elif defined( REGION_AU915 )

#define RF_FREQUENCY                                915000000 // Hz

#elif defined( REGION_CN470 )

#define RF_FREQUENCY                                470000000 // Hz

#elif defined( REGION_CN779 )

#define RF_FREQUENCY                                779000000 // Hz

#elif defined( REGION_EU433 )

#define RF_FREQUENCY                                433000000 // Hz

#elif defined( REGION_EU868 )

#define RF_FREQUENCY                                868000000 // Hz

#elif defined( REGION_KR920 )

#define RF_FREQUENCY                                920000000 // Hz

#elif defined( REGION_IN865 )

#define RF_FREQUENCY                                865000000 // Hz

#elif defined( REGION_US915 )

#define RF_FREQUENCY                                915000000 // Hz

#elif defined( REGION_RU864 )

#define RF_FREQUENCY                                864000000 // Hz

#else
#error "Please define a frequency band in the compiler options."
#endif

#define TX_OUTPUT_POWER 14

#define LORA_BANDWIDTH                              0         // [0: 125 kHz,
//  1: 250 kHz,
//  2: 500 kHz,
//  3: Reserved]
#define LORA_SPREADING_FACTOR                       10         // [SF7..SF12]
#define LORA_CODINGRATE                             1         // [1: 4/5,
//  2: 4/6,
//  3: 4/7,
//  4: 4/8]
#define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT                         5         // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false

#define TX_BUFFER_SIZE 128
#define RX_BUFFER_SIZE 128

```
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<img src="./asset/Radio_setup.png">
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### Note
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Works with STM32CubeIDE Version: 1.8.0, freeRTOS CMSIS_V2, Single-core
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STM32WL55 module only support RFO_H
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RF Switch IC MPN : BGS12SN6E6327XTSA1
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### STM32WL55 Pin map

<img src="./asset/STM32WL55CC_PinMap.png">