27220 Parallax Inc, 27220 Datasheet - Page 121

• Manufacturer Part Number: 27220
• Description: BOOK STAMPWORKS
• Manufacturer: Parallax Inc

Specifications of 27220

• Accessory Type: Booklet
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: StampWorks
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

front end of the PDB’s audio amplifier is a low-pass filter circuit that takes the pure
digital output (a special type of PWM output) from FREQOUT and smoothes it into a
nice sine wave that produces a clean musical note.
To see this in action, build the following circuit:
Using an oscilloscope, monitor the points marked “A” and “B” in the circuit while
running the following short program:
On a stock BS2 this will generate a 440 Hz tone for one second. Note the digital
output at point “A” and the sine-wave produced after the filter circuit at point “B”
(the 10 kΩ resistor represents the audio amplifier input).
Main:
FREQOUT Speaker, 1000, 440
GOTO Main