PICAXE

Frequently Asked Questions

PICAXE FAQ - other sub sections available via the tabs

PICAXE Microcontrollers


What is a PICAXE microcontroller?

A PICAXE microcontroller is a Microchip PIC microcontroller that has been preprogrammed with the PICAXE bootstrap code. The bootstrap code enables the microcontroller to be reprogrammed without the need for an (expensive) conventional programmer, making the whole download system a very low-cost simple serial cable!

For more details please see the What is PICAXE? section.

Where can I purchase PICAXE microcontrollers?

PICAXE microcontrollers can be purchased through the links on this site, from the online store at www.picaxestore.com or from our distributors.

For a list of distributors please see Distributors section.

How fast does the PICAXE operate?

All PICAXE M2 and X2 microcontrollers have an internal resonator which operates at a default of 4MHz for M2 parts and 8MHz for X2 parts.

PICAXE M2 can run up to 32MHz using the internal resonator while PICAXE X2 can run up to 16MHz using the internal resonator and up to 64MHz using an external 16MHz resonator.

At 4MHz the PICAXE chips are executing one million instructions per second internally which, for typical I/O commands such as high, low and toggle, equates to around 4,000 BASIC commands per second. More complicated commands will take longer to execute and therefore fewer of those commands can be executed per second.

Can I overclock the PICAXE?

All parts have an internal resonator allowing operation up to 32MHz for the M2 parts and up to 16MHz for X2 parts.

The X2 parts can also be used with an optional external resonator allowing up to 64MHz operation.

When the X2 parts are used with an external resonator the operating speed will be four times the resonator frequency; for example, for 64MHz operation, specify setfreq em64 and use a 16MHz resonator.

Where are the pinout diagrams?

Please see the PICAXE pinouts section.

What are the PICxx numbers on a PICAXE?

Please see the PICAXE Chip Labels section.

What are the PICAXE electrical characteristics?

The electrical characteristics of the PICAXE microcontroller are dependent upon the base PIC microcontroller used to create the PICAXE microcontroller. Therefore see the relevant Microchip datasheets listed on the PICAXE Chip Labels page.

PICAXE M2 and X2 parts will operate with a power supply of 1.8V up to 5V.

NEVER run your PICAXE directly from a 6V or greater supply as doing so will likely damage or destroy your PICAXE chip and possibly other connected circuitry.

How vulnerable to damage are the PICAXE microcontrollers?

The PICAXE microcontrollers have a high level of static protection built into each pin and so generally handling them without any personal static protection in an educational (non-production) environment is acceptable.

How does the PICAXE handle analogue input?

PICAXE M2 and X2 parts support 8-bit (256 step) ADC using the readadc command and 10-bit (1024 step) ADC using the readadc10 command.

The readadc command giving a byte (8 bit) value allows for ease of use with byte variables (b1 etc.), which makes the maths easier for students. This gives a resolution of about 0.02V (at 5V supply) which is adequate for almost all educational projects.

Does the PICAXE set the watchdog timer fuse?

Yes, the watchdog timer is set and used within a number of commands such as sleep and nap. The user cannot alter its setting.

Does the PICAXE set the power-up timer fuse?

Yes.

Does the PICAXE set the brown-out fuse?

Yes. Both PICAXE M2 and X2 parts have the fuse set. The enablebod and disablebod commands can be used to enable and disable the brown-out function.

Can you supply the PICAXE bootstrap program?

No. The small royalty made on each PICAXE chip sold is the only financial benefit to our company to support the PICAXE system - the software is free and the cables and development kits are sold at very low cost. Therefore we do not allow anyone else to manufacture PICAXE microcontrollers.

What do the PIC and PICAXE abbreviations stand for?

PIC and PICAXE are registered trademarks, they are not abbreviations for any words. The official answer from Microchip's legal department is: "Trademarks are used to identify the source or origin of a product. As such, they are a branding tool. They should be unique and arbitrary rather than descriptive of the product. That said, the PIC trademark has been a registered trademark since 1981. General Instruments was the original owner of the PIC trademark. Microchip acquired ownership of the PIC trademark in 1989. The PIC trademark is the brand name for microcontrollers that Microchip Technology Inc. produces".


The earliest known use of the PICxxxx product naming system was the PIC1650 in the 1977 General Instruments Catalogue. The product in this catalogue is titled 'Programmable Intelligent Computer'...