What do I need to get started?What you need can depend on your project but there are several basics that you will always require, they are:
- A PICAXE Microcontroller.
- A PICAXE Programming Cable.
- A circuit to power the PICAXE and connect your inputs and outputs to.
- A power supply between 3V and 5.5V.
- A computer with PICAXE compatible software and driver software for the programming cable installed.
What are the different chip sizes for?There are several different PICAXE chip types, the 08M2, 18M2 and 20M2. The number at the start describes the number of legs the chip has, this ranges from 8 legs to 20 legs (for ICs stocked by Kitronik), though versions are available with up to 40 legs. The more legs the PICAXE chip has the more inputs and outputs it has. The chart below shows the differences: When it comes to selecting a chip size for a project it is important to make sure it has enough inputs and outputs to fulfil the specification of the project. In general it is better to select a larger chip and have some pins remain unused than to have too few pins to complete the project.
Selecting a circuit for your PICAXE ChipThe easiest way to get started is to buy a development board for the chip size you have selected. This contains the resistors and the connector required to program the chip. A diagram of this can be seen below. Kitronik Development Board. This board gives you an IC socket to put the chip into, terminal blocks for quickly attaching inputs and outputs and an on board stereo jack where the programming cable can be inserted. For the larger PIC chips there are 18 pin development boards and 20 pin development boards.
Drivers for the PICAXE AXE027 Programming CableBefore the AXE027 USB cable can be used on Windows or Mac computers you must install the 'USB driver' software. Linux/Chromebook have a preinstalled driver by default. The USB driver tells the Windows/Mac operating system how to use the USB cable. It is a separate, one-off installation that needs to be carried out the very first time you want to use the cable. Once installed the computer automatically 'remembers' the settings for next time you want to use the cable. The installation is very straight forward:
- Make sure the AXE027 USB cable is not plugged in to the computer.
- Download the drivers for your operating system from this driver download link.
- Run the downloaded driver installation program.
- Insert the AXE027 USB cable and follow the on-screen prompts.
Software for PICAXEFree software is available for download from http://www.picaxe.com/Software/ for programming the PICAXE microcontrollers. The recommended software for Windows at the time of writing is PICAXE Editor V6. Before running the program make sure that the PICAXE cable is plugged in. When the software is ran it will open a window like the one pictured below. From the drop down menus the user needs to select the PICAXE type and the COM port. Clicking the New Flowchart button opens a blank grid allowing the creation of a new program. A simple example of flashing an LED is described below.
TroubleshootingIf the program is not downloading to the PICAXE microcontroller there are a few common mistakes to check for.
- Check the PCB, is the chip in the board the correct way around?
- Is the programming jack all the way in the audio socket?
- Is the board connected to a suitable power supply and switched on?
- On the software, has the correct model of PICAXE chip been selected the from the drop-down menu?
- Has the correct COM port been selected?
- Is the program valid? If the flow chart has ‘dead ends’ it may not compile.
- If the software is being used for the first time, there may be an issue with the driver for the USB cable.
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