Chapter 5. Microbe

Introduction and General Syntax

Microbe compiles programs written in the custom language for PICs, as a companion program to KTechlab. The syntax has been designed to suit a FlowCode program. The syntax for running microbe from the command line is:

microbe [options] [input.microbe] [output.asm]

where options are:

  • --show-source - Puts each line of Microbe source code as a comment in the assembly output before the assembly instructions themselves for that line.

  • --no-optimize - Prevent optimization of the instructions generated from the source. Optimization is usually safe, and so this option is mainly used for debugging.

The .microbe input file must identify the target PIC by inserting the PIC name at the top of the .microbe file; e.g. the name of a PIC16F84 is "P16F84".

Example 5.1. Simple complete Microbe program


a = 0
	PORTA = a
	a = a + 1
until a == 5


Naming conventions

The following rules apply to variable names and labels:

  • They can only contain alphanumerical characters [a..z][A..Z][0..9] and the underscore "_".

  • They are case-sensitive.

  • They cannot start with a number.

  • They should not start with __ (double underscore), as this is reserved for use by the compiler.

Bracing conventions

Curly braces, {}, indicate the start and end of a code block. They can appear anywhere before the start and after the end of the code block. Examples of acceptable code blocks:

statement1 {
	some code

statement2 {
	other code }

	other code

statement5 {
	code block
} statement6


Commenting is similar to C. // comments out the rest of the line. /* and */ denote a multiline comment.

// This is a comment
x = 2 
/* As is this
multiline comment */

Program Structure

The PIC id must be inserted at the top of the program. The end of the main program is denoted with end. Subroutines must placed after end.


A subroutine can be called from anywhere in the code. Syntax:

sub SubName
	// Code...

The subroutine is called with call SubName.