AmForth is an easily extendible command interpreter for the Atmel AVR8 Atmega micro controller family and some variants of the TI MSP430. It has a turnkey feature for embedded use too.

AmForth is published under the GNU Public License v3 (GPL). A commercial use is possible but for traditional commercial uses there are commercial Forths — amForth just is not one of them.

AmForth runs completely on the controller. It does not need additional hardware. It makes no restrictions for hardware extensions that can be connected to the controller. The default command prompt is in a serial terminal.

The command language is Forth. AmForth implements an almost compatible Forth 2012 indirect threading 16bit Forth.

AmForth needs 8 to 12 KB Flash memory, 80 bytes EEPROM, and 200 bytes RAM for the core system. The MSP430 fits into 8KB flash.

Work In Progress

Here you’ll find things that are not yet released but will be part of the next release. See the code section at Sourceforge to get the most recent sources

25.3.2015: release 5.8

  • core(MSP430): new :noname and the defer and value groups of commands.
  • core(All): words with the same name do the same (mostly).
  • core(AVR8): introduce <builds. Together with does> saves one flash erase cycle and makes the source work on the MSP430 as well.

1.2.2015: release 5.7

  • core(ALL): name>interpret and name>compile added. New Recognizer rec:name able to replace rec:word. Uses name tokens (Forth 2012) instead of execution tokens.
  • core(ALL): Lots of bugfixes and regressions. The AVR port should be fully usable again.
  • core(MSP430): restructure of the init process: cold now transfers the data from INFO flash back to RAM if BASE is set and SAVE was executed. That way the user code now correctly survives a restart. SAVE is much like marker that overwrites the previous state and gets no name.

22.12.2014: release 5.6

  • core(AVR): icompare got the same return flag semantics as compare. The leave and ?do forward branches are now resolved at compile time, saves one cell per loop on the return stack at runtime.
  • core(AVR): interrupt vectors are moved from RAM to EEPROM. Saves RAM space and simplifies turnkey actions (remove any int! from your turnkey!)
  • core: re-arranged source files: controller specific and common code.
  • New architecture: MSP430 (G2553) as used in the Texas Instruments LaunchPad 430 with code from Camelforth and 4€4th.
  • core: generalized existing Configuration Stacks in EEPROM into map-stack, get-stack and set-stack. Used for the search order and recognizer stacks.
  • all: changed license to GPLv3.