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Using nRF905 with esp8266-12E

This is how i succeeded using the nRF905 with an esp8266-12E development board.

When using some examples from internet it was not clear to me which pins to connect and how to use the given examples. Then i found RadioHead Packet Radio library for embedded microprocessors. After download and unzip, i placed the files in the Arduino library directory. The examples were then available in the Arduino IDE. With a few modifications to the example code i got it up and running.

The RadioHead file RH_NRF905.h assumes these connections:

Connect the nRF905 to Teensy (or Arduino with suitable level shifters) like this

                 CPU          nRF905 module
                 3V3----------VCC   (3.3V)
             pin D8-----------CE    (chip enable in)
             pin D9-----------TX_EN (transmit enable in)
          SS pin D10----------CSN   (chip select in)
         SCK pin D13----------SCK   (SPI clock in)
        MOSI pin D11----------MOSI  (SPI Data in)
        MISO pin D12----------MISO  (SPI data out)
                 GND----------GND   (ground in)

The esp8266-12E has two SPI ports, but which one is used by RadioHead? And which pin is the SS line? Well, these are the settings which worked for me:

             ESP8266          nRF905 module
                 3V3----------VCC   (3.3V)
             pin D1-----------CE    (chip enable in)
             pin D2-----------TX_EN (transmit enable in)
          SS pin D4-----------CSN   (chip select in)
        HSCK pin D5-----------SCK   (SPI clock in)
        MOSI pin D7-----------MOSI  (SPI Data in)
        MISO pin D6-----------MISO  (SPI data out)
                 GND----------GND   (ground in)

Because of changes to default pins connected to CE, TX_EN and CSN, i had to adapt this in the example code. The RadioHead library supports this during instantiation of the nrf905 object.

// Singleton instance of the radio driver
uint8_t chipEnablePin  = D1;
uint8_t txEnablePin    = D2;
uint8_t slaveSelectPin = D4;
RH_NRF905 nrf905(chipEnablePin, txEnablePin, slaveSelectPin);

In my setup i used the nrf905_client script on a Lolin esp8266-12E V3 board

and the nrf905_server script on a esp8266-12E V2 board.

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