Introduction

Forth is an interesting mix of low-level access tools and language building tools. It is effectively a small toolkit with which you construct a specialized dictionary of words that work together to form your application code. This tutorial will explore and explain the workings of the FlashForth toolkit running on a Microchip PIC18 microcontroller and complements the more hardware-oriented tutorial [1], the FlashForth quick reference [2] and the FlashForth website [3]. Our interest is in using Forth on the microcontroller in an embedded system, such as a special-purpose signal timing device, rather than as part of a general-purpose calculation on a personal computer.

There are quite a number of good introductory tutorials [4,5], course notes [6], and references [7] for programming in forth on a desktop or laptop computer, however, FlashForth running on a PIC18 microcontroller is a different environment. In the following sections, we will follow closely J. V. Noble's tutorial [5], reusing as many of his examples and explanations verbatim, while adapting the overall tutorial to FlashForth.