Can addressing issue

[siz85]

I am trying to address particular on the can network i have created but i am unable to talk to a specific device address. i recieve messages from 1-8 but its from all addresses how would i target a particular address???

sorry im a noob to this and im just piecing together peoples existing code im not sure where to go from here

#include <SPI.h>              //Library for using SPI Communication 
#include <mcp2515.h>          //Library for using CAN Communication (https://github.com/autowp/arduino-mcp2515/)
#include <LiquidCrystal_I2C.h>
 
LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x3F for a 16 chars and 2 line display
 
struct can_frame canMsg;
 
MCP2515 mcp2515(10);                 // SPI CS Pin 10
 
 
void setup()
{
  Serial.begin(9600);                //Begins Serial Communication at 9600 baudrate
  SPI.begin();                       //Begins SPI communication
  lcd.init();
  lcd.clear();         
  lcd.backlight();      // Make sure backlight is on
  lcd.setCursor(0, 0);
  lcd.print("CANBUS TUTORIAL");
  delay(3000);
  lcd.clear();
 
  mcp2515.reset();
  mcp2515.setBitrate(CAN_500KBPS, MCP_8MHZ); //Sets CAN at speed 500KBPS and Clock 8MHz
  mcp2515.setNormalMode();  
  
  
  pinMode(4, OUTPUT);  
  pinMode(5, OUTPUT);     
  pinMode(6, OUTPUT);   
  pinMode(7, OUTPUT); 
      

   //Serial.print("humi");
}
 
void loop()
{
  
  



  if (mcp2515.readMessage(&canMsg) == MCP2515::ERROR_OK) // To receive data (Poll Read)
  {
   
    int x = canMsg.data[0];
    int y = canMsg.data[1];
    int z = canMsg.data[2];
    float a =  z *(5.0/256);
 
   // lcd.setCursor(0, 0);         //Display Temp & Humidity value received at 16x2 LCD
   // lcd.print("Humi: ");
    //lcd.print(x);
   // lcd.setCursor(0, 1);
    //lcd.print("Temp: ");
    //lcd.print(y);
    //delay(1000);
    //lcd.clear();

    Serial.print("  Humidity  ");
    Serial.print(x);
   
    Serial.print("%  ");

    
    Serial.print("  Temp  ");
    Serial.print((y * 9/5) + 32);
    Serial.print("F   ");

   

    //CAN.read(0x700)

    //Serial.print("Temp  ");
    Serial.print(a );
    Serial.println(" V");
    //delay (100);



if (a>= 2)  {
   digitalWrite(4, HIGH);
 
  // sets the digital pin 13 on
 }else {
  digitalWrite(4, LOW);
  }  // sets the digital pin 13 off
  

  if (a>= 2.5)  {
   digitalWrite(5, HIGH);
 
  // sets the digital pin 13 on
 }else {
  digitalWrite(5, LOW);
  }  // sets the digital pin 13 off
  
  if (a>= 3.5)  {
   digitalWrite(6, HIGH);
 
  // sets the digital pin 13 on
 }else {
  digitalWrite(6, LOW);
  }

if (x>= 9)  {
   digitalWrite(7, HIGH);
 
  // sets the digital pin 13 on
 }else {
  digitalWrite(7, LOW);
  }  // sets the dig

  }
}

[Railroader]

What do You mean by reading 1 to 8? Are there 8 devices sending frames?
Can You someway post what the CAN frame looks like, what it contains? I don't have that library in use and don't want to download it to this equipment.

[TomGeorge]

Hi,
What are your devices, if other microcontrollers can you please post their codes?

Can we please have a circuit diagram?
An image of a hand drawn schematic will be fine, include ALL power supplies, component names and pin labels.

Thanks.. Tom...

[mikb55]

Try matching on canMsg.can_id, or if that doesn't compile look at the definition of the can_frame struct to see if there is an address field.

[Hutkikz]

When a message is sent it contains an ID number.
like this one from the CAN_write example from your library:
canMsg.can_id = 0x0F6;
This number should be the chosen ID number of the receiver.

After receiving the message you can do this:

if(canMsg.can_id == 0x0F6 )
 {// This Msg is for this receiver so do stuff here}

[siz85]

Thanks Hutkikz that worked