General Description RFM75 is a GFSK transceiver operating in the world wide ISM frequency band at 2400-2483

5 MHz

Burst mode transmission and up to 2Mbps air data rate make them suitable for applications requiring ultra low power consumption

The embedded packet processing engines enable their full operation with a very simple MCU as a radio system

Auto re-transmission and auto acknowledge give reliable link without any MCU interference

RFM75 operates in TDD mode, either as a transmitter or as a receiver

The RF channel frequency determines the center of the channel used by RFM75

The frequency is set by the RF_CH register in register bank 0 according to the following formula: F0= 2400 + RF_CH (MHz)

The resolution of the RF channel frequency is 1MHz

A transmitter and a receiver must be programmed with the same RF channel frequency to be able to communicate with each other

The output power of RFM75 is set by the RF_PWR bits in the RF_SETUP register

Demodulation is done with embedded data slicer and bit recovery logic

The air data rate can be programmed to 250Kbps, 1Mbps or 2Mbps by RF_DR_HIGH and RF_DR_LOW register

A transmitter and a receiver must be programmed with the same setting

In the following chapters, all registers are in register bank 0 except with explicit claim

Features 2400-2483

5 MHz ISM band operation Support 250Kbps, 1Mbps and 2 Mbps airdata rate Programmable output power Tolerate +/- 60ppm 16 MHz crystal Variable payload length from 1 to 32bytes Automatic packet processing 6 data pipes for 1:6 star networks 1

9V to 3

6V power supply 4-pin SPI interface with maximum 8 MHz clock rate 20-pin 4x4mm QFN package Applications Wireless PC peripherals Wireless gamepads Wireless audio Remote controls Home automation Toys