Memory-wise, the PICAXE chips offer fairly limited capacities compared to the huge memories available in other MCUs. To be fair, however, these devices are aimed more at the educational and hobby/DIY market than professional applications (click here to see a table detailing the capacities and capabilities of the various PICAXE chips.
Apart from bare chips, PICAXE offers various DIY kits and boards to get you started. There is a huge array of gear available, including add-on sensor boards and output devices. For instance, you can get various LCD output modules that only require a one-pin serial connection to the PICAXE.
There are various boards oriented towards specific tasks. The 28X2 PICAXE comes as a 0.3" 28-pin chip, but you can get a 0.6" board containing the 28X2 MCU, download socket, voltage regulator, and reset button that would be ideal for using on a breadboard. You can also get a 28X2 "Shield Base" board, which is compatible with Arduino Shields for expansion. All in all, there's some very tasty stuff indeed (click here to see an index of boards, chips, and kits -- use the small blue links under the "Product Codes" to get more information).
Back to my little kit. I got one of the smaller versions -- the AXE092 kit with the smallest 08M2 chip; three LEDs and a piezo sounder for output; and a switch and an LDR (light-dependent resistor) to provide digital and analog inputs. The assembly was very easy, thanks to the excellent instructions, and it would be even for someone with little electronics experience. Power is from a small 3xAA battery box (4.5V), though you could also use a 3-5V power supply. My kit's programming lead was serial (there is a USB version now, which is probably why my kit was so cheap!) But you can make up your own serial lead if you wish. Here is a schematic of my kit:
(Click here to see a larger, more detailed image.)
Observe that the schematic refers to the chip as an 08M, which is an older chip; mine came with the latest 08M2. The programming pins are 2 (Rx) and 7 (Tx). As you can see, Pin 7 (= port 0) is also used as a digital output. You can use the programming input, Pin 2 (= port 5, not shown above) for other purposes, but you then have to reset the chip (or use the BASIC DISCONNECT command) before programming it again. The AXE092 kit does not appear in the list I mentioned above -- I think it's been discontinued (again, this is probably why I got it so cheap), but there is a small User Manual available.
A photo of the AXE092 board is shown below (note that this photo was taken from the manual -- the LEDs on the board I built stand up straight and my resistors are all oriented the same way, LOL):
The AXE092 PICAXE Kit. The big black thing at the upper left is the programming socket. The small black thing at the lower left is a push switch. The DIP switch is for disconnecting outputs to use them for other things. The upper wires on the right-hand side go to the battery; wires on the lower right-hand side go to a piezo sounder.
It was at this point that I ran into my first problem -- I found my PC did not have a serial port. The Device Manager said that I did, but I could not find "hide or hair" of it. My motherboard manual also said I had such a port, but I discovered that was for a previous board version. Fortunately, I had a USB-to-Serial adapter knocking around, so I got that out.
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