On bigger assembler programs you get confused about the RAM usage: Which adresses and amount of RAM was used from which functions.

Then it was time to switch to C.

C make all variables reservation and overlaying fully automatically for you. Also which registers must be PUSHed and POPed was no longer a question for you.

Thus C was ideal to work on bigger programs.

On the 8051, if the code size grows up to about 4kB, then it was time to switch to C.


If you can use a very good compiler, e.g. the Keil C51, then already small projects of only 2kB can benefit from C, e.g. on the AT89C2051.


Peter