Innovation First, Inc.
EDU-RC & Motherboard Reference Guide
11.8.2002
www.InnovationFirst.com
Page 7
7. PWM Outputs
The Isaac16 EDU Motherboard has eight 4-pin PWM connectors. The PWM outputs are most
commonly used to drive Multi-Speed Motors. These outputs can cause the speed to vary on the Multi-
Speed Motors in a range from Full Forward, to Full Reverse, or Off. The Multi-Speed Motors can be
connected directly to the PWM outputs. Be sure to connect the cable so the black wire is on the
indicated pin (on the right side of the connector).
The PWM outputs can also drive the Victor 883 Speed controller. The Victor 883 can be connected
directly to the PWM outputs. Use a 3-wire PWM/Relay extension cable to connect a speed controller or
servo to one of the PWM output ports. When connecting a Victor speed controller, use the right 3 pins
of a PWM port. Be sure to connect the cable so the black wire is on the indicated pin (on the right side
of the connector).
Caution: The center right pin and the left pin on the PWM connector is connected to the Battery
input voltage. Depending on your battery, this voltage may be too high for servos and some speed
controllers. We recommend you disconnect the center wire on a 3-wire cable when connecting to
other manufacturers speed controllers. You must then supply the required voltage, if needed, for
that specific speed controller. Disconnecting the center wire is not necessary for the Victor 883.
Most servos are rated at 4.8V to 6.0V. The total current draw on all PWM and Relay +Battery
pins is limited to 11 Amps by the Motherboard’s circuit breaker.
Shown below is the PWM port pin-out to aid in the connection of a Multi-Speed Motor or a Victor 883
Speed Controller to a PWM output.
Multi-Speed Motor Victor 883 Speed Controller
Connection Connection
Table 7: PWM Output Map
PWM
Port
Shaft
Rotation
PBASIC
Variable
Pin
Location
Wire
Color
PWM1
CCW
p1_y Center
Right
White
PWM2
CW
p3_y Center
Right
White
PWM3
CCW
p1_y Center
Right
White
PWM4
CW
p3_y Center
Right
White
PWM5
CW
p1_x Center
Right
White
PWM6
CW
p3_x Center
Right
White
PWM7
CCW
p1_wheel Center
Right
White
PWM8
CCW
p3_wheel Center
Right
White
+Battery
(Orange)
Ground
(Black)
Ground
(Black)
PWM Control
(White)
+Battery
(Red)
+Battery -
Not Required
(Red)
PWM Control
(White)
Not Used