The PWMPAL is an intelligent peripheral that adds up to four PWM output channels and up to four control/counter input channels to the 24-pin BASIC Stamp microcontroller. Our customers described the PWMPAL as a sort of saddle for the BASIC Stamp module. Communication with the PWMPAL is handled through a bi-directional serial connection on pin P0 of the BASIC Stamp microcontroller.

Features:

• Up to four simultaneous PWM outputs
• Up to four 16-bit counters
• Independent control of each PWM output high-time, low-time and phase
• Generate frequencies from 0.3 Hz to 20 kHz; duty cycle independent at some frequencies
• The PWM channels can be configured to operate under software control, or under hardware control through the corresponding counter input channel
• Requires no PCB "real estate" – mounts underneath BASIC Stamp module
• Auto-baud detection (9600, 19.2K, 38.4K ) for BASIC Stamp to PWMPAL communication

Key Specifications:

• Power Requirements: 5 VDC @ ~20 mA
• Communication: Asynchronous serial (AppMod protocol supported)
• Package Type: 24-pin DIP (.600")
• Operating Temperature: +32 to +158°F (0 to +70°C)

Example Applications:

• Servo or DC motor control (using H-Bridge) for robotics
• AC square wave generation
• Background counting for process control, motion monitoring, etc.

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

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