I have the following code:
clr
mov red1 mem1
mul mem1 2
mov mem1 out

and feeding A=1 using a constant combinator
I can see that mem1 is set to A=2, as expected
but nothing is being output from the microcontroller. What am I missing?

I'm confused even more than you.

Suddenly, mul doesn't seem to work properly with the memory
mul mem4 2

Why you use constant combinator instead of RAM module?

but nothing is being output from the microcontroller

I'm going to pull out old examples.

out seems broken

Fixed out, published new version.

Perhaps, I'll restore my sanity tomorrow and add some examples.

Fixed output for all MicroControllers, download new version.

Very soon

Added new examples in the scenario

Thank you for fixing it. It works now.
The manual says I can connect up two 4 external RAM modules, but it seems only north and south RAMs are recognized.

Unrelated: cut-n-paste of the module looses the program, is there a way to make module cut-n-pastable (by construction robots)?

cut-n-paste of the module looses the program, is there a way to make module cut-n-pastable (by construction robots)?

Still nope, I did something similar (I'm not sure that it works fine)