What is PICAXE?

Sizes and Variants of PICAXE Chips

PICAXE Chip Sizes

PICAXE ChipsPICAXE chips come in two series – the M2 and X2 series – and 6 physical sizes (8, 14, 18, 20, 28, 40 pin).

The M2 series chips are the standard devices allowing up to 1800 lines of BASIC code and common interfacing protocols such as RS232 (serial), infra-red and I2C. They also support parallel task processing. The X2 series have a larger memory capacity for longer programs and more variables (RAM). They also have a few more advanced interfacing protocols such as ‘1-wire’ and ‘UNIO’.

The main difference between the sizes is that there are, as you would expect, more input/output pins on the larger chips. So normally you would identify how many inputs/outputs your project requires and then select the chip accordingly.

On all M2 and X2 parts most of the pins can be user-configured to be an output, input, analogue input or touch sensor input. See the pinout diagrams for more details.

The following table gives a brief summary of the various PICAXE chips.
For a more detailed comparison please see the PICAXE manuals

Feature 08M2 14M2 18M2 20M2 20X2 28X2 40X2
Memory Capacity (bytes) 2048 2048 x2 2048 x2 2048 x2 4096 4096 x4 4096 x4
RAM (bytes) 128 512 512 512 256 1280 1280
Byte Variables (bytes) 28 28 28 28 56 56 56
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
I2C Yes Yes Yes Yes Yes Yes Yes
Tune (ring tones) 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 same software, BASIC language and USB download cable is shared between all the PICAXE chips.

 

Skinny DIP Cartoon

PICAXE Chip Case Style

All PICAXE Chips are available in both Dual-In-Line (through-hole) and surface mount casing formats. The following table gives the casing styles for each size chip.

Kindly note the 28 pin format is the 300mil 'skinny DIP' format, not the wider 600 mil 28 pin format.

 

 

 

PICAXE Chip
DIL Casing Surface Mount Casing
08M2 300 mil / 7.62 mm PDIP 150 mil / 3.81 mm SOIC
14M2 300 mil / 7.62 mm PDIP 150 mil / 3.81 mm SOIC
18M2 300 mil / 7.62 mm PDIP 300 mil / 7.62 mm SOIC
20M2 / 20X2 300 mil / 7.62 mm PDIP 300 mil / 7.62 mm SOIC
28X2 300 mil / 7.62 mm SPDIP 300 mil / 7.62 mm SOIC
40X2 600 mil / 15.24 mm PDIP 44pin 2mm TQFP