Cette page est inspirée de penguintutor.com Using Raspberry Pi and Arduino together through SPI serial communications

import spidev
import time
 
spi_bus = 0
spi_device = 0
spi = spidev.SpiDev()
spi.open(spi_bus, spi_device)
spi.max_speed_hz = 1000000
 
# Send a null byte to check for value
send_byte = 0x80
rcv_byte = spi.xfer2([send_byte])
# repeat to check for a response
rcv_byte = spi.xfer2([send_byte])
data_recv = rcv_byte[0]
if (data_recv != 0x80):
    print ("Unable to communicate with Arduino "+str(data_recv))
    quit()
 
 
# Data is sent as single bytearray
# lower 4 bits = pin number
# returns a value that is used to set a digital pin
# pin = Arduino pin number
# state = True for high, False for low
# returns byte or 0xff = invalid
def req_set_digital (pin, state):
    if (pin < 0 or pin > 10):
        return 0xff
    if (state == True):
        pin += 0x60
    else :
        pin += 0x20
    return pin
 
# read analog pin
def req_read_analog (pin):
    if (pin < 0 or pin > 5):
        return 0xff
    return pin + 0x10
 
# read digital pin
def req_read_digital (pin):
    if (pin < 0 or pin > 10):
        return 0xff
    return pin
 
while True:
    # Turn LEDs on
    for i in range (3, 10) :
        send_byte = req_set_digital (i, True)
        rcv_byte = spi.xfer2([send_byte])
        time.sleep (0.5)
    # Turn back off again
    for i in range (3, 10) :
        send_byte = req_set_digital (i, False)
        rcv_byte = spi.xfer2([send_byte])
        time.sleep (0.5)
    # Get status of pin 2
    send_byte = req_read_digital(2)
    rcv_byte = spi.xfer2([send_byte])
    # Delay to allow Arduino to get answer ready
    time.sleep (0.25)
    # Send null request
    send_byte = 0xf0
    rcv_byte = spi.xfer2([send_byte])
    print ("Value of digital pin 2 is "+str(rcv_byte[0]))
 
    # Get status of analog 0
    send_byte = req_read_analog(0)
    rcv_byte = spi.xfer2([send_byte])
    # Delay to allow Arduino to get answer ready
    time.sleep (0.25)
    # Send null request
    send_byte = 0xf0
    rcv_byte = spi.xfer2([send_byte])
    print ("Value of A0 is "+str(rcv_byte[0]))

# include <SPI.h>
 
void setup() 
{
  // Set the Main in Secondary Out as an output
  pinMode(MISO, OUTPUT);
  // turn on SPI as a secondary
  // Set appropriate bit in SPI Control Register
  SPCR |= _BV(SPE);
}
 
// The following code is then used to receive a byte and then set the data register to return a byte to the master controller device.
void loop () 
{
  byte in_byte;
  // SPIF indicates transmission complete (byte received)
  if ((SPSR & (1 << SPIF)) != 0)
  {
    in_byte = SPDR;
    // Handle the input code here
    // Set return_val to the value you want to return
    SPDR = return_val;
  }