The first steps require an ATmega micro controller or a TI Launchpad 430 with a MSP430G2553 controller. The AVR needs a separate RS232 connection to an PC, the MSP430 works with the USB connection for both the command terminal and the reprogramming.
amforth has a simple user interface. It is available as a serial port.
> cold amforth 5.0 ATmega16 8000 kHz > words nr> n>r (i!) !i @i @e !e nip not s>d up! up@ ... >