So far in ESE101, I’ve introduced a fictional microcontroller that has three instructions: ADD, SUB, and MOVE. The microcontroller uses three simple steps to run each instruction from memory and then move on to the next instruction in memory.
Until now we assumed instructions would be executed sequentially (in order), but this week we’ll add a few new instructions that will let our microcontroller jump around to whichever instruction it wants to.
We’ll start our Embedded Software Engineering 101 journey with the humble microcontroller. The microcontroller (or microprocessor) is the fundamental building block of all computer systems, embedded or otherwise.
A microcontroller seems quite complicated, but it’s made up of three simple things: instructions, registers, and memory. Instructions are the things a microcontroller knows how to do. A simple microcontroller doesn’t know how to do much - it might only have 20 or 30 instructions. I’ll use the MSP430 microcontroller made by Texas Instruments later in this series, and it has only 27 instructions.
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