User Manual

6. The Maestro Scripting Language

A script is a sequence of commands that is executed by the Maestro. Commands can set servo

targets, speeds, and accelerations, retrieve input values, and perform mathematical computations.

Basic control structures – looping and conditionals – are available for use in making complicated

scripts. The Maestro script language is a simple stack-based language very similar to FORTH, and

scripts compile to a compact bytecode in which commands and subroutine calls each take just a single

byte. A basic editor/debugger is available in the Script tab of the Maestro Control Center application.

6.a. Maestro Script Language Basics

Commands and the stack

A program in the Maestro script language consists of a sequence of commands which act on a stack of

values. Values in the stack are integers from -32768 to +32767. On the Micro Maestro 6-channel servo

controller, there is room for up to 32 values on the stack, while on the Mini Maestro servo controllers

there is room for up to 126 values on the stack. Commands always act on the topmost values of

the stack and leave their results on the top of the stack. The simplest kind of commands are literals,

numerical values that are placed directly onto the stack. For example, the program “-10 20 35 0” puts

the values -10, 20, 35, and 0 sequentially onto the stack, so that it looks like this:

value

3 0

2 35

1 20

0 -10

A more complicated command is the PLUS command, which adds the top two numbers, leaving the

result on the top of the stack. Suppose the numbers 1, 2, 4, and 7 are sequentially placed on the stack,

and the PLUS command is run. The following table shows the result:

before after

3 7

2 4 11

1 2 2

0 1 1

6. The Maestro Scripting Language Page 69 of 102