RFM22B Radio Module

[Dick Ivers]

I bought two of these radios to set up as a simple one-way communication link using PIC micros as the data source/receive on each end. I've done the same with radios from Ciseco and that works well. These RFM22B units are less expensive, so they would be better for a production situation.

I'm having trouble setting the radio configuration, in particular the radio frequency and channel select. The documentation from HopeRF is not helping much. Does anyone have experience with these modules?

[Dick Ivers]

Found this thread with some good information including working code:
http://www.picbasic.co.uk/forum/show...ghlight=rfm22b

Still have questions though ... need to contact the author

[Ioannis]

I am struggling with these modules too. I found that the registers need to set everytime the module is powered on.

There is no way of storing in a Non-Volatile memory.

Trying now to figure out how to set the frequency. Too many parameters...

Ioannis

[Dick Ivers]

Ioannis,
Yes, the registers are not permanent. The configuration needs to be written in to your pic code so the registers will be set on start up. The problem is there are 128 registers. I don't think they all need to be set. There are some with default settings that are OK as is. This is what I'm trying to figure out.

I know how to set the frequency. Give me your frequency band and I'll show you how. There is an online spreadsheet that makes it easy:
http://www.hoperf.com/upload/rf/RF22...s_RevB1-v5.xls

[Ioannis]

Hi Dick.

Thanks for the link. Yes indeed it makes it easier.

My band is the 433MHz (Europe ISM band for radio telemetry and Remote controls).

My modules are different but the command set is the same. I am testing the RFM23BBPS.

Ioannis

[Dick Ivers]

Ioannis,

You're welcome. Using the spreadsheet for 433 mhz I get the following register settings:

75h $53 with sideband select set
75h $13 with sideband select not set
76h 4B
77h 00

All the example code I have found uses the sideband select. Not sure why, but I'm doing same. My radios are using 915 mhz (ISM band for USA).

I am also using the high power RFM23BP, but on the sending end only. I need the small size RFM22B on the receiver side.

Dick