SX1231 Calculator

I was doing some testing with a Semtech SX1231 (also known as RFM69*) to
replace the Silicon Labs Si443x receiver I am currently using to receive my 433
MHz sensor nodes. The SX1231 seems to have much better reception and less
craziness in the FIFO control.

While configuring the module I found that some configuration options have
constrains on them that are a bit hidden away in the datasheet text. This is
especially annoying if you want to change some setting after a while and don’t
want to reread the whole datasheet.

So I decided to write a little configuration calculator for the chip. The
calculator converts human readable values to the register values and verifies
that they meet the constraints. It also automatically updates register values
of options that depend on a specific setting(eg. Crystal frequency or Carrier
Frequency).

It also allows importing register dumps so you can easily see what
configuration you are using. And it tries to visualize some of the parameters,
like packet structure and RF spectrum.

The calculator is build as a single page web application. Which means you can
use it in any modern browser. Because it is fully written in client side
javascript you don’t even need an internet connection/or need to thrust a
remote server to use it.

Writing the code was, as usual, much more work than I anticipated for. It
involved a lot of bit fiddling and copy and paste, which is rather error prone.
So be warned to verify the results, before usage.

Well enough talking, I suggestion you just try it out! The online version is available here:

SX1231 Calculator

If you want to use it offline, then you can just download the page from the online version.

The sources is of course available at GitHub

IC’s used on HopeRF modules

HopeRF makes some nice modules. But I’m always struggling to find which actual chip is used by the HopeRF radio modules. So I made a little list of HopeRF modules and the name of the IC used.

Module IC
RFM12 Silicon Labs Si4420
RFM12b Silicon Labs Si4421
RFM22b Silicon Labs Si4432
RFM23b Silicon Labs Si4431
RFM24w Silicon Labs Si446x(?)
RFM26w Silicon Labs Si446x(?)
RFM31b Silicon Labs Si4330
RFM42b Silicon Labs Si4032
RFM43b Silicon Labs Si4031
RFM50 Silicon Labs Si1000(?)
RFM60 Silicon Labs Si4010
RFM63W Semtech SX1211
RFM64W Semtech SX1212
RFM65W Semtech SX1239
RFM66W Semtech SX1232
RFM67W Semtech SX1230
RFM68W Semtech SX1243
RFM69W Semtech SX1231

This information is based on:

  • The title of the earlier Hope RF data sheets often contains the Silicon labs chip name
  • Comparing data sheets

Of course I give no guarantees about the correctness of this information. If you find something to be incorrect, please leave a comment.