RFu-328 Technical Data

Technical Data

Arduino Board type for uplaod: Arduino Uno

Dimensions: 2.53mm x 22mm x 27.70mm (or 35.5mm long with chip antenna)


Electrical characteristics

  • Supply voltage:
    • Minimum 3.3v
    • Maximum 3.6v (5v if no radio is installed)
    • Absolute maximum limit 3.9v
  • Current consumption:
    • ATMega running & SRF transmitting 28.9mA

    • ATMega running & SRF receiving 31.2mA

    • ATMega running & SRF sleeping (ATSM2) 7.1mA

    • ATMega sleeping (powerdown + WDT wake) & SRF sleeping (ATSM2) 4.7uA


RF characteristics

  • 868 and 915 MHz ISM/SRD bands (can support 315, 433, 900 MHz)
  • Over the air data rate of 250Kbps with a max of 500Kbps
  • Up to 10dBm (10 mW) power


Pin out

The RFu has 20 pins versus the 32 pins available on the XinoRF and the Arduino Uno. Most of the normal Arduino pins are accesable on the RFu.

Here is a handy table that shows you which pins are present:

 RFu328 pinXinoRF pinArduino Uno Function
 19D3D3/PWM/interupt 1
 20D2D2/interupt 0


 SRF-RF EnableD8D8



If you wish to program with an FTDI style interface you will need to put a 0.1uf capacitor between the interface DTR and pin 5 (RESET) this is the same technique employed on the Arduino, this gives your interface the ability to auto reset the module which is required to invoke the Arduino bootloader. Alternatively look at our new 4 in 1 Explorer Plus USB interface which has an XBee style socket, FTDI style connector and built in SRF-U which has an RFu Auto Reset enable jumper as well as support for conventional XBee/XRF type devices.


Over the air programming

The RFu supports over the air programming of the ATMega328 processor if there's a serial version of the SRF installed, SPI devices eg RFM12B cannot do remote uploads.

The RFu is shipped ready for OTAMP with the following settings

  • Baud Rate (ATBD):- 115200
  • ID (ATMY):- --
  • Channel offset(ATRC):- 3

Note RFµ-328's shipped before 8th July 2013 had an ATMY of 'RF'