Différences

Ci-dessous, les différences entre deux révisions de la page.

--- spi_documentation_2 [2022/05/30 13:13] – serge
+++ spi_documentation_2 [2022/05/31 07:45] (Version actuelle) – serge
@@ Ligne 1: / Ligne 1: @@
 ====== Communication entre Raspberry Pi et Arduino en SPI ======
+<WRAP center round box 60% centeralign>
+**{{tagpage>spi|Toutes les pages sur protocol SPI}}**
+</WRAP>
+=====Une ESP32 n'est pas une carte Arduino=====
+**Les sketchs ci-dessous ne fonctionnent pas avec une ESP32**
+=====Exemple 1=====
+https://roboticsbackend.com/raspberry-pi-master-arduino-uno-slave-spi-communication-with-wiringpi/
+Raspberry Pi (master) Arduino Uno (slave) SPI communication with WiringPi
+<code csharp>
+#include <SPI.h>
+void setup() {
+  // have to send on master in, *slave out*
+  pinMode(MISO, OUTPUT);
+  // turn on SPI in slave mode
+  SPCR |= _BV(SPE);
+  // turn on interrupts
+  SPI.attachInterrupt();
+}
+// SPI interrupt routine
+ISR (SPI_STC_vect)
+{
+  byte c = SPDR;
+  SPDR = c+10;
+}  // end of interrupt service routine (ISR) for SPI
+void loop () { }
+</code>
+**Raspberry Pi avec wiringPi**
+<code>
+#include <iostream>
+#include <wiringPiSPI.h>
+#define SPI_CHANNEL 0
+#define SPI_CLOCK_SPEED 1000000
+int main(int argc, char **argv)
+{
+    int fd = wiringPiSPISetupMode(SPI_CHANNEL, SPI_CLOCK_SPEED, 0);
+    if (fd == -1) {
+        std::cout << "Failed to init SPI communication.\n";
+        return -1;
+    }
+    std::cout << "SPI communication successfully setup.\n";
+    unsigned char buf[2] = { 23, 0 };
+    wiringPiSPIDataRW(SPI_CHANNEL, buf, 2);
+    std::cout << "Data returned: " << +buf[1] << "\n";
+    return 0;
+}
+</code>
+Voir le lien pour la compilation de wiringPi et de ce script
+=====Exemple 2=====
+Tiré de [[http://www.penguintutor.com/electronics/rpi-arduino-spi|penguintutor.com Using Raspberry Pi and Arduino together through SPI serial communications]]**\\
+Arduino: SPCR et SPDR pas défini !
+====Raspberry====
+<code python>
+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]))
+</code>
+====Arduino====
+<code csharp>
+#include <SPI.h>
+// track if digital pins are set as input or output (saves reading registers)
+// Pins 0 to 9 can be used, pin 10 can be used for SS (but can be used if that's not required)
+bool pin_output[11];
+void setup()
+{
+  // by default all pins are inputs
+  for (int i=0; i<11; i++)
+  {
+    pin_output[i] = false;
+  }
+  // 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);
+}
+void loop ()
+{ char print_text [50];
+  byte in_byte;
+  // SPIF indicates transmission complete (byte received)
+  if ((SPSR & (1 << SPIF)) != 0)
+  {
+    in_byte = SPDR;
+    // if no action bit sent then return same
+    if (in_byte & 0x80) SPDR = in_byte;
+    // if write set
+    else if (in_byte & 0x20)
+    {
+      // set digital pin output - use mask to extract pin and output
+      if (set_digital_pin (in_byte & 0x0F, in_byte & 0x40) != 0xFF) SPDR = in_byte;
+    }
+    // If value is only pin numbers then digital read
+    else if (in_byte < 0x10)
+    {
+      byte return_val = read_digital_pin (in_byte);
+      SPDR = return_val;
+    }
+    else if ((in_byte & 0x10) && !(in_byte & 0x20))
+    {
+      byte return_val = read_analog_pin (in_byte & 0x0F);
+      SPDR = return_val;
+    }
+    else // Otherwise an error - return 0xff
+    {
+      SPDR = 0xFF;
+    }}}
+byte set_digital_pin (byte address, bool high_value)
+{
+  if (address < 0 || address > 10) return 0xFF;
+  // Is it currently set as output - if not then set to output
+  if (!pin_output[address])
+  {
+    pinMode(address, OUTPUT);
+    pin_output[address] = true;
+  }
+  // set to low if 0, otherwise 1
+  if (high_value == 0) digitalWrite(address, LOW);
+  else digitalWrite (address, HIGH);
+}
+// Returns 1 for high and 0 for low
+// If invalid then returns 0xff
+byte read_digital_pin (byte address)
+{
+  if (address < 0 || address > 10) return 0xFF;
+  // if currently output then change to input
+  if (pin_output[address])
+  {
+    pinMode(address, INPUT);
+    pin_output[address] = false;
+  }
+  return digitalRead (address);
+}
+// As full byte is used for value there is no invalid value
+// If invalid then returns 0x00
+byte read_analog_pin (byte address)
+{
+  if (address < 0 || address > 5) return 0x00;
+  int analog_val = analogRead (address);
+  // Analog value is between 0 and 1024 - div by 4 for byte
+  return (analog_val / 4);
+}
+</code>
 {{tag> communication sb spi }}