Learn program logic handheld.

I have a TI-56 from 1978 that I learned a LOT of programming from in a short period just because I had the thing with me most of the time and I got breaks now and then. It is an interpreter that lets you record buttons pressed as instructions in sequence then lets you play it back. It has goto and conditional loops and a countdown loop, all on buttons too.

I kick around the idea of a cheap handheld virtual machine interpreter/programmable base machine (wired for addons) that they program with button presses and run, can save to EEPROM (SD optional).
How much display and who would extra like more than one line cut off? Make both kinds.

Being a learn to program machine, it should use hex, hehe, get it over quick.
Also I think an 8 bit instruction and 16-bit user word size. Show hex by default.

It needs digit buttons, math ops buttons, logic ops, time,… memory and serial access buttons.

And big concern to me is to teach non-blocking. No button code should block >10us.

Instead of a single linear program to read and array store serial then printing the array…

Have one program that reads serial as available and stores it, flags end of entry.
Have another program that sees the flag and prints the buffer.

The difference being how easy it is to add a blinking status led to either.

If it could be easy to add onto, sensors, etc, that would just be cool.

Any comments?