This document provides an overview of prototyping with a Raspberry Pi, including common operating systems, programming languages, GPIO pin usage, sensors, motors, I2C, PWM, SPI, and UART communication protocols. It discusses connecting an LED and button to the GPIO pins, as well as code examples for blinking an LED, reading a button press, and communicating via I2C, SPI, and UART. The online community is highlighted as a key benefit of the Raspberry Pi platform.

1. Prototipare col
Raspberry Pi
Gabriele Guizzardi
guizzardi@gmail.com

2. Perché?
Il costo?
La potenza?
I linguaggi o i vari sistemi operativi?
LA COMUNITA’ ONLINE!!!

3. Sensori

4. Motori

5. Principali Sistemi Operativi
Raspbian (da Debian)
Ubuntu Mate
Snappy Ubuntu Core
Arch Linux Arc
Gentoo
Debian ARM
Windows 10 IoT (Pi 2)

6. Principali linguaggi con libreria per la GPIO
Python (RPi.GPIO)
C (wiringPi)
Processing (processing.io.*)
Java (Pi4J)
da riga di comando o Bash usando i relativi files (/sys/class/gpio/….)

7. La GPIO

8. Nomenclatura dei pin

9. Accendere
un LED

10. Accendere un LED import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BOARD)
GPIO.setup(7, GPIO.OUT)
# ciclo 10 volte, on/off di 1 sec.
for i in range(10):
GPIO.output(7,True)
time.sleep(1)
GPIO.output(7,False)
time.sleep(1)
GPIO.cleanup()

11. Accendere un LED

12. Pulsanti

13. Pulsanti
Pull Down
Pull Up

14. Pulsanti
import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM) # Broadcom SOC channel
GPIO.setup(4, GPIO.IN, pull_up_down=GPIO.PUD_UP)
while True:
input_state = GPIO.input(4)
if input_state == False:
print('Pulsante premuto')
time.sleep(0.5)

15. I2C (inter integrated circuit)
MAX
112

16. I2C

17. I2C

18. I2C

19. IC2 #!/usr/bin/python
import smbus
bus = smbus.SMBus(1) # 0 oppure 1 se RPi è 256 o 512 Mb di RAM
DEVICE_ADDRESS = 0x70 # indirizzo 7 bit
DEVICE_REG_MODE1 = 0x00
DEVICE_REG_LEDOUT0 = 0x1d
#Scrive un singolo char [long write_byte_data(int addr,char cmd,char val)]
bus.write_byte_data(DEVICE_ADDRESS, DEVICE_REG_MODE1, 0x80)
#Lettura
(msb, lsb, xsb) = bus.read_i2c_block_data(addr, REG_MSB, 3)

20. PWM (pulse-width modulation)

21. PWM (duty-cycle)

22. PWM
def color(R, G, B):
# range colore da 0-100%
RED.ChangeDutyCycle(R)
GREEN.ChangeDutyCycle(G)
BLUE.ChangeDutyCycle(B)
# spegne tutti i LED
time.sleep(.02)
RED.ChangeDutyCycle(0)
GREEN.ChangeDutyCycle(0)
BLUE.ChangeDutyCycle(0)
# Settaggio dei pin come output
GPIO.setup(17, GPIO.OUT)
GPIO.setup(18, GPIO.OUT)
GPIO.setup(27, GPIO.OUT)
RED = GPIO.PWM(17, 100) # 100Hz
RED.start(0) # 0 = spento
GREEN = GPIO.PWM(18, 100)
GREEN.start(0)
BLUE = GPIO.PWM(27, 100)
BLUE.start(0)
while 1:
for r in range(0,2):
for g in range(0,2):
for b in range(0,2):
# loop per il 100% di ogni colore
for i in range(0,101):
color((x*i),(y*i),(z*i))

23. SPI (serial peripheral interface)

24. SPI

25. SPI
#!/usr/bin/python
import spidev
import time
spi = spidev.SpiDev()
spi.open(0, 0)
spi.max_speed_hz = 7629
# Divide un intero in un array di 2 byte per spedirlo via SPI
def write_pot(input):
msb = input >> 8
lsb = input & 0xFF
spi.xfer([msb, lsb])
# Loop infinito di apertura/chiusura della porta del MCP4151
while True:
write_pot(0x1FF)
time.sleep(0.5)
write_put(0x00)
time.sleep(0.5)

26. UART Universal Async. Receiver-Transmitter

27. UART

28. UART
import serial
ser = serial.Serial("/dev/ttyAMA0")
ser.write("messaggio da spedire")
read = ser.read()
print read
ser.close()