Question

What is the Picaxe? What are the different types available and what are the differences between the different models? How can they be used?

Answer 1

PICAXE is a microcontroller system based on microchip PIC microcontrollers, pre-programmed with PICAXE bootstrap code. There is no need for a conventional programmer because the microcontroller can be reprogrammed with the bootstrap code. They are widely used by students for electronic projects in schools because of ease of use.

The first PICAXE was developed by Clive Seager and was based on PIC16F872 microcontroller. BASIC which stands for Beginner's All-purpose Symbolic Instruction Code, and is the first high-level programming language that many people learn. It is much easier to learn and debug than industrial programming languages. This is why Basic was chosen for PICAXE. It helped expand the user base of microcontrollers. The simplicity and the power of BASIC made it the right choice for the PICAXE system.

PICAXE is programmed via a 3-wire connection to the computer’s serial port. The operational PICAXE circuit uses just a few components and can be easily constructed on a breadboard or PCB design. All that is required is a three-wire download cable, either USB or serial, depending upon which port type is available on the computer being used.The code itself is a version of BASIC, which is easy to learn and use, and quite powerful.

PICAXE chips are pre-programmed and tested Microchip PIC microcontrollers. The PICAXE system can be used with different physical sizes of PICAXE chip (8, 14, 18, 20, 28 and 40 pin). The primary difference between the sizes of chips is the number of input/output pins available.

The different types available are:

PICAXE-08M2, PICAXE-14M2, PICAXE-18M, PICAXE-20M2, PICAXE-20X2, PICAXE-28X2, PICAXE-40X2.

Comparison of different types of PICAXE:

Feature	08M2	14M2	18M2	20M2	20X2	28X2	40X2
Memory Range in bytes	2048	2048 x2	2048 x2	2048 x2	4096	4096 x4	4096 x4
RAM capacity in bytes	128	512	512	512	256	1280	1280
Input/Outputs Pins	6	12	16	18	18	22	33
ADC/Touch Pins	3	7	10	11	11	16	27
Max. Freq. (MHz)	32	32	32	32	64	64	64
Serial In/Out	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Infrared In/Out	Yes	Yes	Yes	Yes	Yes	Yes	Yes
Parallel Tasks	4	8	8	8	1	1	1
Program Slots	1	2	2	2	1	4	4

The entry level µCs are the 08M2, 14M2, 18M2, and 20M2; the advanced level includes the 20X2, 28X2, and the 40X2 which are used for bigger projects.