Motors - BeagleBone - page 234

The L293D also has an enable pin (pin 9, on the lower right), which is used to control the
speed of the motor by using a PWM signal. (See Recipe 4.2 for details on how this
works.)
At the end of the code, the process.on() function at the end of the code detects when
the user has pressed ^C (Ctrl-C), stops the timer, and turns off the motor. If you don't turn
off the motor, it will continue to spin.
NOTE
The previous example uses a motor that works with 3.3 V. What if you have a 5 V motor?
The banded wire (running from P9_7 to pin 8 of the L293D) in Figure 4-6 attaches the
L293D to the Bone's 5 V power supply. This will work if your motor doesn't draw too much
current.
If 5 V isn't enough voltage, or if the Bone can't supply the current needed, Figure 4-7 shows
how to use an external power supply.