Samuel A Clarke.com

Review article: ‘Robotics: Intro to PICAXE’

In my article entitled ‘Robotics: Intro to PICAXE’ I started out with a generalized description of the various PICAXE microcontrollers available from Revolution Education Ltd.. Here I would like to expand slightly and take a bit more In-depth look at the PICAXE microcontrollers. First starting with the ‘Standard Use’ class, then moving on to the ‘Advanced Use’ class after that. Revolution Education Ltd. has changed their previous categories from ‘Education, Standard, Advanced Use’ and combined ‘Education and Standard Use’ into one category. The M2 and X1 microchips are classified as the ‘Standard Use’ class, while the X2 series of microchips are classified as the ‘Advanced Use’ class of microcontrollers.

As of the writhing of this article, you still can purchase several of the older PICAXE microcontrollers, namely: the ‘PICAXE-08M Module’, ‘PICAXE-08 microcontroller’, ‘PICAXE-08 microcontroller (5 pack)’, ‘PICAXE-08 microcontroller (50 pack) [Only available to educational account holders.]’, ‘PICAXE-18X microcontroller’, ‘PICAXE-18X microcontroller (10 pack)’, ‘PICAXE-18M microcontroller (25 pack)’, and the ‘PICAXE-20M microcontroller (22 pack) [Only available to educational account holders.]’. I would suggest however that you stick to the the new PICAXE microcontrollers as they are richer in features, power, and cost LESS in many cases than the older discontinued PICAXE microcontrollers. (I am unsure how long the X1 parts will be available and would suggest moving up to either an X2 part or an M2 part instead)

In the table below you will see the stats for the standard class of PICAXE microcontrollers:

PICAXE Type	IC Size	Memory	I/O Pins	Outputs	Inputs	ADC	Memory(Data)	Polled Interrupt
08M2	8 pin	2048	6*	6*	6*	3	256(Shared)	YES
14M2	14 pin	2048	11*	11*	11*	7	256	YES
18M2	18 pin	2048	16*	16*	16*	10	256(Shared)	YES
20M2	20 pin	2048	16*	16*	16*	11	256	YES
28X1	28 pin	1000-3200	23	9-17	0-12	0-4	128+i2c	YES
40X1	40 pin	1000-3200	32	9-17	8-20	3-7	128+i2c	YES

(NOTE: the top speed of the M2 Series is 32MHz and the X1 series is 20MHz)
(NOTE: * Input/Output Pins are configurable as either)

Follow @Samuel_A_Clarke

Just ‘a buck’ 😉

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

Advanced:(2000-3200 line memory, per ea. of (up to) 4 separate slots)

PICAXE uPU : –	Total I/O Pins : –	Max ADC Pins : –	Max Speed :
20X2	18 configurable	0-8	64MHz
28X2	22 configurable	0-16	64MHz
40X2	33 configurable	0-27	64MHz

____________________________________________________________

We will examine the different individual PICAXE microcontroller chips and their individual capabilities in more detail in my next post…