PICAXE
PICAXE is a microcontroller system based on a range of Microchip PIC microcontrollers. PICAXE devices are Microchip PIC devices with pre-programmed firmware that enables bootloading of code directly from a PC, simplifying hobbyist embedded development (not unlike the Arduino and Parallax BASIC Stamp systems). PICAXE devices have been produced by Revolution Education (Rev-Ed) since 1999. There are currently six (6) PICAXE variants of differing pin counts (8-14-18-20-28-40) and are available as DIL and SMD. PICAXE microcontrollers are pre-programmed with an interpreter similar to the BASIC Stamp but using internal EEPROM instead, thus reducing cost. This also allows downloads to be made with a simple serial connection which eliminates the need for a PIC programmer. PICAXE is programmed using an RS-232 serial cable or a USB cable which connects a computer to the download circuit, which normally uses a 3.5 mm jack and two resistors. PICAXE microcontrollers are programmed using BASIC. The PICAXE interpreter features bit-banged communications: Serial (asynchronous serial) SPI (synchronous serial) Infrared (using a 38 kHz carrier, seven data bits and five ID bits) One-wire The "readtemp" command reads the temperature from a DS18B20 temperature sensor and converts it into Celsius. All current PICAXEs have commands for using hardware features of the underlying PIC microcontrollers: Hardware asynchronous serial Hardware synchronous serial Hardware PWM DAC ADC SR Latch Timers (two on X2/X1 parts which have settable intervals, only one on M2 parts with a fixed interval, older parts have none) Comparators Internal temperature measurement All current PICAXE chips have at least 2048 bytes of on board program memory available for user programs: 08M2 - 2048 bytes 14M2 - 2048 18M2+ - 2048 20M2 - 2048 20X2 - 4096 28X1 - 4096 40X1 - 4096 28X2 - 4096 per slot with four slots for a total of 16 KiB 40X2 - 4096 per slot with four slots for a total of 16 KiB The default clock speed for all M2 and X1 parts is 4 MHz and for the X2 parts is 8 MHz.
