not sure how interested you might be to port uLisp onto another microcontroller… ? one of the microcontrollers i use and really like is the multicore Parallax Propeller, which comes in 2 generation versions.
i’ve got both, altho i have only one 2nd gen board at the mo, but i have quite a few of the gen 1 boards. the prop1 chip also comes in a DIP version, which is super cheap & easy to make on a tiny breadboard, i made one up to test and it worked first time.
Eric R Smith has made a v small Lisp for it which is bundled with his free FlexProp IDE. short extract of the info =>
"proplisp implements a version of Lisp that is like, but not exactly, Scheme. A lot of useful features are left out. The only data types are numbers, strings (delimited by double quotes), symbols, builtin functions, lambda functions, and of course pairs.
Numbers are only 28 bits (the other 4 bits are used for tag values)."
I can confirm his Lisp runs on the Propeller 1, have not tried compiling & running it on the Prop 2 yet.
interestingly too, the 2nd gen Propeller 2 has a built in Forth interpreter in the boot ROM :)