Wednesday, July 17, 2013

Bare Bones Propeller


The Bare Bones Propeller is a minimum circuit designed for a series of step by step expansions.

It will run at RC speeds, has great reliability, and uses programs that output to virtual LEDs and a terminal. The provided program is one example that uses a terminal to display data.

The circuit required a stable power supply and the adding of two filtering and decoupling capacitors. We chose to add these to the power supply leads to avoid clutter on the first schematic. In a series of step by step upgrades, the bare bones schematic will be expanded. Each schematic will show one addition for clarity.

Read the text next to the schematic because it has information about attaching two filtering/decoupling capacitors. The pictorial is from the Parallax PEK manual revision 3 and shows actual breadboard wiring for power and ground connections (VSS/VDD) of one side of the Propeller chip to the other.

Also shown is the program's output showing the on off blinking of a Terminal LED. In the example on page 38 of the PEK manual, the crystal shown at the right, is not needed. The value of filtering capacitors, also known as decoupling capacitors (these capacitors have multiple functions) is .1uf.