Raspberry Pi 研習營

CAVE Education

徐豐智

E-mail:jesusvictory777@cavedu,com

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Session 6: GPIO

http://elinux.org/RPi_Low-

level_peripherals

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Introduction

• R-Pi offers lower-level interfaces intended to

connect more directly with chips and subsystem

modules

• Signals on the 2x13 header pins include SPI,

I2C, serial UART, 3V3 and 5V power

• Not "plug and play" and require care to avoid

miswiring

• The pins use a 3.3V logic level and are not

tolerant of 5V levels, such as you might find on a

5V powered Arduino

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GPIO

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• Not yet software-enabled are the

flex cable connectors with CSI

(camera serial interface) and DSI

(display serial interface), and a

serial link inside the HDMI

connector called CEC

• They provide 8 GPIO pins plus

access to I²C, SPI, UART), as well

as +3.3 V, +5 V and GND supply

lines5

RPi Serial Connection

• The following parameters are needed to connect to the Pi console, and

apply on both Linux and Windows.

– Speed (baud rate): 115200

– Bits: 8

– Parity: None

– Stop Bits: 1

– Flow Control: None

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http://elinux.org/RPi_Serial_Connection

Connection to a microcontroller

or other peripheral• The TxD and RxD signals can also be connected directly

to similar signals on a microcontroller board like the

Arduino provided the signals are all at 3V3 levels.

• It's still a good idea to put 2K2 series resistors in the

lines to prevent damage when two outputs are

connected together, which could also happen if a GPIO

input pin is accidentally programmed as output.

• If your microcontroller uses 5V logic levels, level

conversion is usually necessary - see 'Connecting to a

PC' for details.

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控制GPIO腳位

http://makezine.com/projects/tutori

al-raspberry-pi-gpio-pins-and-

python/

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安裝GPIO for python函式庫

• 安裝python函式庫

• $sudo apt-get install RPi.GPIO

• Python的.py檔匯入函式庫

• import RPi.GPIO as GPIO

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GPIO example:LED blink

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• 接上LED，注意GPIO針腳是否接對

GPIO example:LED blink

• 新增.py檔，gpio_led.py

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GPIO example:LED blink

• 設定初始狀態，GPIO針腳

• import RPi.GPIO as GPIO #匯入函式庫

• import time #匯入函式庫

• GPIO.setwarnings(False) #關閉偵錯模式

• GPIO.setmode(GPIO.BCM) #設定腳位代號

• GPIO.setup(17,GPIO.OUT) #17號為輸出腳

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GPIO example:LED blink

• LED燈閃爍設定

• while True: #無限迴圈

• GPIO.output(17,True) #17腳輸出電壓(3.3V)

• time.sleep(2) #停頓2秒

• GPIO.output(17,False) #17腳不輸出電壓(0V)

• time.sleep(2)

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GPIO example:Button

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• 接上Button，注意GPIO針腳是否接對

GPIO example:Button

• 更改gpio_led.py

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GPIO example:Button

• 設定初始狀態，GPIO針腳

• import RPi.GPIO as GPIO ＃匯入函式庫

• import time ＃匯入函式庫

• GPIO.setwarnings(False) ＃關閉偵錯模式

• GPIO.setmode(GPIO.BCM) ＃設定腳位代號

• GPIO.setup(18,GPIO.IN) ＃18號為輸入腳

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GPIO example:Button

• 偵測Button是否被按下

• while True:

• input_value=GPIO.input(18) ＃讀取18號輸入腳，並存入變數中

• if input_value ==False: ＃如果讀取為０Ｖ

• print( "The button has been pressed" )

• while input_value == False: ＃讀取為0V時，進入迴圈

• input_value = GPIO.input(18)

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GPIO example:Led_Button

• Button+LED

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GPIO example:Led_Button

• 新增.py檔，gpio_button.py

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GPIO example:Led_Button

• 設定初始狀態，GPIO針腳

• import RPi.GPIO as GPIO ＃匯入函式庫

• import time ＃匯入函式庫

• GPIO.setwarnings(False) ＃關閉偵錯模式

• GPIO.setmode(GPIO.BCM) ＃設定腳位代號

• GPIO.setup(18,GPIO.IN) ＃18號為輸入腳

• GPIO.setup(17,GPIO.OUT) #17號為輸出腳

• GPIO.output(17,False) #17號為0V(燈不亮)

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GPIO example:Led_Button

• 設定初始狀態，GPIO針腳

• while True:

• input_value=GPIO.input(18) #儲存18號輸入腳(按鈕)於變數

• if input_value ==False: #如果按鈕被按下

• print( "The button has been pressed,Lighting LED." )

• GPIO.output(17,True) #17號輸出腳給電(LED燈亮)

• while input_value == False: #按鈕被按下時進入迴圈

• input_value = GPIO.input(18) #讀取按鈕的狀態，存於變數中

• print( "The button has been pressed,Extiguishing LED." )

• if input_value == True : #如果按鈕沒被按下

• GPIO.output(17,False) # 17號輸出腳為零(LED燈暗)

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GPIO控制直流馬達

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(1)使用PWM控制直流馬達

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(1)pwm.py

• 新增檔案

• pwm.py

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(1)pwm.py

• GPIO.setup(18,GPIO.OUT)

• #設定通道

• p = GPIO.PWM(18,100)

• #設定頻率

• p.start(b)

• #設定Dutycycle

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(2)直流馬達+驅動IC

• 接上馬達驅動IC，L293D。

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(2)直流馬達+驅動IC

• 注意樹莓派宣告的位置

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(2)直流馬達+驅動IC

• 接上馬達驅動IC，L293D。

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(2)直流馬達+驅動IC

• 連接Rpi電源

• 與馬達外接電源

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(2)直流馬達+驅動IC

• 連接直流馬達

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(2)直流馬達+驅動IC

• 新增檔案L293D.py

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(2)直流馬達+驅動IC

• 第二組馬達連接IC

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(2)直流馬達+驅動IC

• 連接第二組馬達

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(3)pwm+驅動IC

• 新增檔案pwm2.py

• 可從pwm.py改

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Raspberry Pi - Installing a

RS232 Serial Port

http://www.savagehomeautomatio

n.com/projects/raspberry-pi-

installing-a-rs232-serial-port.html

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Raspberry Pi - RS232 Serial

Interface Options (Revisit)

SOFTWARE USE OF THE

SERIAL PORT

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make of backup of the two files

that we intend to modify• sudo cp /boot/cmdline.txt

/boot/cmdline.bak

• sudo cp /etc/inittab /etc/inittab.bak

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Next

• we need to remove the "console=ttyAMA0,115200" and

"kgdboc=ttyAMA0,115200" configuration parameters from the

"/boot/cmdline.txt" configuration file.

• To edit the file use this command:

$ sudo nano /boot/cmdline.txt• The file probably contains this default configuration line:

– dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200

console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait

• After removing the two configuration parameters, it will look similar

to this:

– dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4

elevator=deadline rootwait

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Last

• edit the "/etc/inittab" file and comment out

the use of the "ttyAMA0" serial port.

• To edit the file use this command:

$ sudo nano /etc/inittab

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Now towards the bottom of the file, look for a

configuration line that includes the "ttyAMA0" port

address

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Place a pound sign ("#") in front of the line to comment it

out. With a pound sign ("#") at the beginning of the line,

Linux will ignore this configuration line.

• Save the "/etc/inittab" file and then issue

this command to reboot the Raspberry Pi:

$ sudo reboot

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• Now you are ready to use the serial port

with a software application and the

operating system won't interfere with the

port.

• Use the device address "ttyAMA0" in your

application to access this serial port.

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Project:Create an internet

controlled robot using

Livebotshttp://www.instructables.com/id/Cr

eate-an-internet-controlled-robot-

using-Livebots/step1/Have-Fun/

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Advanced GPIO for the

Raspberry Pi

https://pypi.python.org/pypi/RPIO

Extends RPi.GPIO with PWM,

GPIO interrups, TCP socket

interrupts, command line tools and

more

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RPIO is an advanced GPIO module

for the Raspberry Pi• PWM via DMA (up to 1µs resolution)

• GPIO input and output (drop-in replacement for RPi.GPIO)

• GPIO interrupts (callbacks when events occur on input gpios)

• TCP socket interrupts (callbacks when tcp socket clients send data)

• Command-line tools rpio and rpio-curses

• Well documented, fast source code with minimal CPU usage

• Open source (LGPLv3+)

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RPIO的範例網站

http://pythonhosted.org/RPIO/

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接線圖

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Installation

• $ sudo apt-get install python-setuptools

• $ sudo easy_install -U RPIO

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LXTerminal中，使用nano編輯程式test.py

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下指令 $ sudo python test.py，接到pin 11的LED以每0.1秒閃爍

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思考RPIO.cleanup()指令

釋放GPIO的channel

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How to use GPIOs on

raspberry pi (Simple I/O, PWM

and UART)

https://sites.google.com/site/semill

eroadt/raspberry-pi-tutorials/gpio

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