I’m pleased to announce a big step forward for the open source MMDVM project. There is now support for the ADF7021 RF chip. A lot of work has been going on in the background. A special shout out needs to go to Andy CA6JAU. Without his countless hours of work this would remain a half finished project still sitting on my workbench.
This means mmdvmhost/mmdvm can now talk directly to the 7021 chip so external radios are not needed. In the initial release of source code, there is support for DStar, DMR (DMO), Fusion and P25. Fusion and P25 have not had any significant amount of testing done.
Now to the good stuff. All the source code is currently hosted on Andy’s github.
We will be working on getting it merged into the mainline code.
I also posted in the Files section a document with build and installation instructions.
The hardware used during development is a combination of an ADF7021 board and an STM32F103 board. To make it easier to put the parts together I designed a simple carrier board (see attached picture). Everything is thru-hole so most everyone should be able to solder it. As soon as the Chinese New Year break is over, Bruce will be ordering more blank boards.
The stock ADF7021 board needs two modifications. The first is the oscillator has to be replaced with a low ppm TCXO. The second mod is a jumper needed to connect a pin on the 7021 chip to the NC pin on the ADF7021 board header. More pictures will be coming shortly.
The ADF7021 boards are no longer being manufactured. Through his connections in China Bruce has acquired a small number of them and is currently having the two modifications done. His supplier claims to still have some remaining stock. If there is enough interest from the group I’m sure he can try to get more.
If you are interested in helping to test, PM Bruce. He will be in touch with updates on kit availability. We’d like to give priority to those who are more comfortable with the ins and outs of setting up the build environment and able to do the soldering.