The PWMPAL is an intelligent peripheral that adds up to four PWM output channels and up to four control/counter input channels to the BASIC Stamp microcontroller. A BASIC Stamp module is required to use the PWMPAL and is sold separately. Our beta customers described the PWMPAL as a sort of saddle for the BASIC Stamp module.

The PWM channels can be configured to operate under software control, or under hardware control through the corresponding counter input channel.  In addition to PWM waveform generation, the PWMPAL has four 16-bit counters that operate at all times, even when the counter pin is used for hardware PWM control.

Communication with the PWMPAL is handled through a bi-directional serial connection on pin P0 of the BASIC Stamp microcontroller.The Parallax AppMod communications protocol is used, allowing baud rates of 9600, 19,200 and 38,400 baud.

Examples of PWMPAL Uses:

• Servo or DC motor control for robotics and animatronics.
• AC waveform [square wave] generation for bi-color LEDs and sensors.
• Background counting for process control, robotic motion monitoring, etc.

Features:

• Up to four simultaneous PWM outputs.
• Independent control of each PWM output high-time, low-time, and phase.
• Generate frequencies from 0.3 Hz to 20 kHz; duty cycle independent.*
• Outputs may operate under software or hardware control.
• Up to four 16-bit counters.
• Auto-baud detection (9600, 19.2K, 38.4K) for Stamp-to-PWMPAL communications.
• Requires no PCB "real estate" – mounts underneath BASIC Stamp module.

*Duty cycle independence is not available for the entire range of output frequencies.

Downloads:
PWMPAL Documentation (.pdf)
PWMPAL Source Code (.zip)
N&V column "Get your Motor Runnin" #100 (.pdf)