Copyright 2018 Jason Woodford, VO1JWW. Uses the AtomThreads scheduler, Copyright 2010 Kelvin Lawson. GNU Time module is Copyright 2012 Michael Duane Rice. APRS is a trademark of Bob Bruninga, WB4APR. All rights reserved.
The JDigi project is an attempt to put an entire amateur radio AX.25 stack with both digipeating and APRS functions into an embedded platform, such as the AVR series of microcontrollers. Many of these platforms (AVR in particular) have very limited RAM, so JDigi has been written to be very efficient with memory.
JDigi is essentially a group of applications that run on top of the AtomThreads scheduler - a multi-threading platform that can run on several embedded architectures. This allows JDigi to be a multi-platform project that only requires architecture dependent modules to deal with low-level functions. The core of AtomThreads is located in kernel/.
JDigi has been split into two trees: a platform independent Core, and the platform dependent modules which provide the functions required by Core. The core of JDigi is located in jdigi/. Please note that many of these modules still presume the use of a separate Program Memory area (PROGMEM) to reduce RAM usage when space is limited. This may reduce the platform independent design of this code.
All architecture dependent modules (both AtomThreads and JDigi) are located in ports/XXX/, where XXX is the AtomThreads provided sub-folder that contains it's architecture dependent stuff. Currently, the only supported platform is the ATMega2560 due to it's "large" RAM amount. However, an earlier prototype used the ATMega32 with success. Therefore, it is possible to create a stripped-down version that can operate in smaller RAM space. Note that devices with 32K of Program Memory will need to omit many RAM and PROGMEM hungry Core modules.
This uses the same build structure as AtomThreads. Each ports/XXX/ folder contains it's own Makefile for building JDigi. Each Makefile should be customized for the architecture and programmer being used.
For example, the currently supported platform for AVR is the ATMega2560 Arduino Mega, using a parallel port Pony STK200 programmer. To build the project, change to the ports/avr folder and:
- Edit the various header files to suit your particular setup.
- Edit the local Makefile for the programming interface and part ID.
- Build the code:
make. - Document the code:
make doxygen. - Upload the code:
make progdude app=jdigi. - Verify the upload:
make progdudetest app=jdigi. - Upload EEPROM code using
make progdudeee app=jdigi.