Robotics – Intro To PICAXE

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In my previous post I discussed what a microcontroller is, what a microcontroller consists of, and also a few common types of microcontrollers. In this post I would like to explore the PICAXE microcontroller from Revolution Education Ltd. A PICAXE microcontroller is a standard Microchip PICmicro microcontroller that has been pre-programmed with the PICAXE bootstrap code. The bootstrap code enables the PICAXE microcontroller to be re-programmed directly via a simple serial connection - eliminating the need for an expensive conventional programmer. This makes the whole download system into a very low-cost and simple serial download cable.

Why the PICAXE microcontroller from from Re-Ed.? Well, the PICAXE is a cheap, easy, and a surprisingly capable microcontroller. For just a few dollars, a simple download cable and free programming software available from Re-Ed. you can be up and running with the PICAXE microcontroller. You also get many advanced features with the PICAXE microcontroller such as; parallel multi-tasking, servo support, I2C interfacing, musical ring-tone tune support, ADC inputs, touch sensor inputs, and also standard, infra-red, and serial input/output pins to mention just a few.

The PICAXE microcontroller comes in several different sizes and variants. You can choose between 8, 14, 18, 20, 28, and 40 pin sizes and either standard DIP or SMT packages. There is also a special 28 pin DIP 'module' that contains a PICAXE-28X2 (PIC18F25K22) chip, voltage regulator, download socket, and reset switch all in one convenient package Ideal for breadboarding. The variants available are 'M2', 'X1', and 'X2'. The older 08, 14, 18 and 20 pin ‘A’, ‘M’ and ‘X’ parts are no longer manufactured as
they have now been superseded by the M2 parts and the older 28 and 40 pin ‘A’ and ‘X’ parts are no longer manufactured and they have now been superseded by the X1 and X2 parts. There is still an 08'M' module available but I suspect this will be discontinued soon and replaced with an 08M2 module. You can also get an 18'X' but this has been replaced by the 18M2 and most likely will be phased out unavailable soon. For more detailed information and to checkout the different project boards available see the Revolution Education Ltd. website.

[The following table shows the primary functional differences between the available PICAXE microcontrollers:]

(For general ‘hobbyist’ the M2 and X2 series are recommended.)

Standard:(800 - 1800 line memory)

PICAXE uPU : -	Total I/O Pins : -	Max ADC Pins : -	Max Speed :
08M2	5 configurable	0-3	32MHz
14M2	11 configurable	0-7	32MHz
18M2	16 configurable	0-10	32MHz
20M2	16 configurable	0-11	32MHz
28X1	0-12in,9-17out	0-4	20MHz
40X1	8-20in,9-17out	3-7	20MHz