The PICAXE-20M IC is part of the mid-range educational lineup of PICAXE chips. It offers:
80 lines memory
4 8/10-bit Analog-to-Digital converters (ADC)
8MHz maximum operation speed (4MHz normally)
Digital temperature sensors
Plays user-defined musical tones
PWM Motor control
Input Pulse counting
Serial output & debugging via programming cable
Based on the PIC 16F677 IC
It's a solid microcontroller for those medium projects where you don't need the extra power of an "X" series chip!
The ‘PICAXE’ system is a powerful, low cost microcontroller programming system designed to simplify educational and hobbyist use of microcontrollers. PICAXE chips can be programmed in a graphical 'flow-chart' environment or in easy to understand BASIC.
Memory (lines)= Approximate number of lines of program code the chip can hold. Data Memory= Bytes of EEPROM memory on board. "128 (-Prog)" means 128 Bytes less the space needed for your program. 256+I2C means 256 Bytes + any external EEPROM space you add via the I2C interface). Polled Interrupt= A process that automatically checks a pin in between each command to see if something has happened (very useful!)
The PICAXE is a great chip, but the programming interface is a bit bizarre, using a 1/8" stereo jack. Last time we looked, breadboards didn't have stereo jacks... Good thing these adapters are available!