AmForth is an easily extendible command interpreter for the
Atmel AVR8 Atmega micro controller family and some variants of the TI MSP430.
The RISC-V CPU (32bit) is currently beeing worked on. 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 for the AVR8 needs 8 to 12 KB Flash memory, 80 bytes EEPROM, and 200 bytes RAM for the core system. A similar code for the MSP430 fits into 8KB flash. The MSP430 info flash is used for similar purposes as the EEPROM for the AVR8 platform.
The 32-bit variants for ARM and RISC-V are experimental. They share most of the high-level code with the 16-bit variants.
AmForth website: http://amforth.sourceforge.net/