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Programming the BeagleBone

You're reading from  Programming the BeagleBone

Product type Book
Published in Jan 2016
Publisher
ISBN-13 9781784390013
Pages 180 pages
Edition 1st Edition
Languages

Table of Contents (21) Chapters

Programming the BeagleBone
Credits
About the Author
Acknowledgment
About the Reviewers
www.PacktPub.com
Preface
1. Cloud9 IDE 2. Blinking Onboard LEDs 3. Blinking External LEDs 4. Controlling LED Using a Push Button 5. Reading from Analog Sensors 6. PWM – Writing Analog Information 7. Internet of Things with BeagleBone 8. Physical Computing in Python 9. UART, I2C, and SPI Programming 10. Internet of Things using Python GPIO Control in Bash BeagleBone Capes
Pinmux and the Device Tree Index

Writing on analog components


BoneScript provides the function analogWrite() to generate a PWM wave on any GPIO pin from the previous diagram. After a call to analogWrite(), the pin will generate PWM waves of a specified duty cycle. Here is the prototype of the analogWrite() function.

The code is as follows:

analogWrite(pin, value, [freq],[callback])

Where

pin – BeagleBone pin identifier string

value – duty cycle ratio of the PWM as value between 0 and 1

freq – frequency of PWM in Hz

callback – name of function which will be called automatically when analogWrite() finishes.

Here, freq and callback parameters are optional. If freq is not specified, the default value 2 kHz is used. The duty cycle ratio value is not taken as a percentage but as a ratio between 0 to 1. It is a ratio of time it was ON to period. We can get that by dividing the percentage value by 100. So, a 50% duty cycle will be 0.5 value. Sometimes, you need to read the datasheet of the analog output device to find out the correct...

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