Basic Stamp 2 Architecture

POWER

The BS2 needs a stable 5V DC to function properly.
The Stamp Stack and the Board of Education have internal 5V regulators. That means that in theory you can power them with 4.8V to ~12V.
These internal regulators cannot serve as a regulated power supply for other electronic components of your circuits. You MUST use another regulator. 7805 is recommended in such situations and will give you around 1.5A of current at 5V.

PROGRAMMING INTERFACE

The BS2 communicates with the computer using serial communication. Usually people upload their code in the BS2 using a standard serial cable.

INPUT/OUTPUT

The BS2 has 16 pins that can be set to input or output.

Setting a pin to input will have it expect a signal (5V or nothing). For example, you could use a simple switch that sends 5V to the input pin of the BS2 when it is on and nothing when it is off. It is very important that you do not sent 5V directly into a pin of the BS2. That would cause a short circuit and could kill your BS2. To remedy to this problem, always use a resistor (10KOhm should be enough).

Setting a pin to output will allow you to send 5V or to ground whatever is connected to the pin. The current sent by a BS2 pin is around 20mA. It is sufficient to power most LEDs but not high enough to power a DC motor.

MEMORY

The BASIC Stamp has two kinds of memory; RAM (for variables used by your program) and EEPROM (for storing the program itself). EEPROM may also be used to store long-term data in much the same way that desktop computers use a hard drive to hold both programs and files. An important distinction between RAM and EEPROM is this:

• RAM loses its contents when the BASIC Stamp loses power; when
  power returns, all RAM locations are cleared to 0s.
• EEPROM retains the contents of memory, with or without power,
  until it is overwritten (such as during the program-downloading
  process or with a WRITE instruction.)