ZIO, Motherboard User Manual
Rev. 2.0
Zilogic Systems
Page 16
RC = 1 / (2 F)
For an output frequency of 1kHz, choosing R = 4kohm, C = 0.04uF.
DC Motor Control.
A DC motor’s speed and direction of rotation can be controlled using the
PWM port. The DC motor has to be interfaced through a circuit called the H-Bridge. A simple H-
Bridge constructed using switches is shown in the following diagram. By controlling, the switches
the motor can be made to rotate forward, reverse, brake, and free run. The various switch states
and their effect on the motor is shown in the following table.
S1
S2
S3
S4
Function
0
0
0
0
Free-run
0
1
1
0
Reverse
1
0
0
1
Forward
0
1
0
1
Brake
1
0
1
0
Brake
Forward
The current to flows in one direction through the motor.
