RFM22/23 modules – introduction
RFM22, the bigger brother of RFM12, is based on (probably) Si4432 chip. It has acclaimed +17dBm output power, which enabling to provide high effective RF range. It is powered from 3.3V rail. SPI clock max is about 12.5MHz (40ns/40ns SCLK timing).
Considering these modules as a radio link, you should become familiar with :
HopeRF datasheet : http://www.hoperf.com/upfile/RFM22.PDF
HopeRF TX demo : http://www.hoperf.com/upfile/RFM22_transmit_DEMO.pdf
HopeRF RX demo : http://www.hoperf.com/upfile/RFM22_receive_DEMO.pdf
SiLabs WDS : http://www.silabs.com/products/wireless/EZRadio/Pages/WirelessDevelopmentSuite.aspx
SiLabs Application Notes : AN415 – EZRadioPRO Programming Guide (see Google).
Don’t pay too much attention to HopeRF demos… These are similarly unclear to RFM12 related ones.
RFM22 has many interesting features, e.g. Automatic Packet Handling, which allows you to forget about TX/RX state machines sending/receiving headers/crcs/datas. Simply, send your data into module’s FIFO, turn on TX, and download it from RX side’ FIFO. Like a cable link.
More details incoming soon, incl. PIC32MX RFM22 library.
Gobotronics's Blog 
Hello,
What is the difference between RFM22 and RFM22B?
RFM22 has +17dBm output power, whereas RFM22B has +20dBm.
Both modules operates at 3.3V nominal.
Thank you! Keep up the good work you’re doing with your blog!
Thanks!
hello..can you help me make a code?
hello! I’m working on rfm22 but i am not that code in programming..can you help me in making the code for my work??
Hi… How can I use this product with CCS C?
Hi. I don’t know the specifity of CCS C. The library uses hardware or software SPI port implementation, so this is the firts thing you should review. Another point would be IRQ handler. If you’d like to use interrupt approach then you should write proper int handler and call rfm22_handle_irq().