This document discusses using .NET to control blinken lights and GPIO pins on a Raspberry Pi. It provides an overview of GPIO concepts like voltage, digital pins for output and input, and communication protocols. It then demonstrates examples with .NET's System.Device.GPIO library to turn an LED on and off, read a push button, and interface with a temperature sensor and LED array using I2C and SPI protocols. The document emphasizes that .NET GPIO programming is similar but requires Linux/ARM targeting for Raspberry Pi.

1. Blinken' Lights with .NET
Scott Holden

2. ./GPIO
General-purpose input/output.

3. Voltage
Battery
Power Source
Positive
Negative
Vcc
Gnd
5v
3.3v

4. Digital Pins - Output
• 2 states, HIGH or LOW
• 1 or 0, true or false
• At high, Vcc
• At low, Gnd
• This depends, but is fine as a concept

5. ./RaspiDemo/0-BashGPIO
Turn on all the lights!
Pin 20
Gnd
LED
Resistor

6. Recap
• /sys/class/gpio… directory
• ‘export’ pins to enable them
• echo 20 > ./export
• ‘direction’ defines input/output
• echo out > ./gpio20/direction
• ‘value’ defines high/low
• echo 1 > ./gpio20/value

7. ./System.Device.GPIO
Less bash, more sharp!

8. System.Device.GPIO
• github.com/dotnet/iot
• src/System.Device.Gpio – Main NuGet package
• src/devices – Devices NuGet package
• Abstraction from OS/Hardware
• Different binding for each platform
• Still in experimental stage

9. ./Targets/Raspi
Same but different?

10. Targeting a RaspberryPi
• Linux, not windows
• ARM32/64, not x86
• Recommendations:
• linux-arm runtime identifier
• Self-contained
• Publish profiles are great!

11. ./RaspiDemo/1-SimpleLight
On, off, on, off...
Pin 20
Gnd
LED
Resistor

12. Recap
• Setup GpioController
• new GpioController()
• ‘Open’ pins before use
• controller.OpenPin(x)
• Set the pin ‘mode’ to output
• controller.SetPinMode(x, PinMode.Output)
• ‘Write’ to the pin to turn it on
• controller.Write(x, PinValue.High)

13. Digital Pins - Input
• 2 states, HIGH or LOW
• 1 or 0, true or false
• At high, Vcc-ish is expected*
• At low, Gnd-ish is expected*
• Pull-up/pull-down
• Connecting to Vcc/Ground internally

14. ./RaspiDemo/2-PushButton
Don’t press the big red button!
Pin 5
Gnd Switch
Vcc Resistor
Resistor

15. Recap
• Setup GpioController
• new GpioController()
• ‘Open’ pins before use
• controller.OpenPin(x)
• Set the pin ‘mode’ to input
• controller.SetPinMode(x, PinMode.Input)
• ‘Read’ the pin to check if it is on
• controller.Read(x) == PinValue.High

16. ./RaspiDemo/3-Reaction
How fast is too fast?
Pin 5
Gnd Switch
Vcc Resistor
ResistorPin 20 LED Resistor
Pin 22 LED Resistor

17. ./BeyondGPIO
1-wire, 2 wire, 3 wire, 4!

18. Communication Protocols
• 1-wire
• Simple low speed signaling
• I2C
• Primary chips/devices, One or more secondary
• 2 wires, simple signaling
• SPI
• 4 wires: data in, data out, clock & chip select

19. ./RaspiDemo/4-TempApi
1-wire is more than enough!
Vcc
Pin 13
Gnd
DHT11
Sensor
1-wire

20. ./RaspiDemo/5-LEDArray
Shine on!
Vcc
MOSI
LED
Matrix
Gnd
CLK
CE0

21. ./FinalNotes

22. Differences
!=

23. Getting Started
• RaspberryPi
• MicroSD card
• 5v power source
• Breakout cable*
• Jumpers/leads
• Breadboard
• Sensors/lights/switches/motors

24. ./Thanks
github.com/ScottHolden