[dragontamer]

Yes but... modern 8051 has grossly different peripherals / drivers than the original.

Most of your code / effort will be in getting these peripherals to work. A ton of microcontroller programming is a simple if(voltage>0.5V) then {setup peripherals to do Y}.

In fact, voltage > 0.5V is a peripheral (aka: the Analog Comparator + DAC loopback) on most uCs today. So in practice its:

"If (analog comparator) then {do Y}".

Except "if analog comparator" is itself an interrupt that you put into the interrupt table, so that the processor can sleep for minimum power usage. So really its all just configuration of interrupt table handlers, configuration of various peripherals, and then a massive amounts of sleep.