Connected a DAC to an Arduino Uno

@frenchstudent

If I were you I would start by reading about the Wire.h library and the associated functions on the Arduino Website.

https://www.arduino.cc/en/Reference/Wire

You might want to bear in mind that the Arduino Uno cannot be further than 1 metre from the I2C module that you are communicating with. If the connecting wires are more than 1 metre, the data transfer becomes unstable.

I already read the library but i never used this language so it is complicated to begin with. Nevertheless i succeeded to do the basics on the I²C but in some videos and commentary i saw only the connection between 2 Arduino Uno board and for me i just need to connect to a DAC. But i can't give some instructions to the DAC, so is it always a slaveor not?

@frenchstudent In addition to Pugwash advice, this pdf presents the I2C bus.

And you may also want to have a look at the source code of another DAC/I2C library like miniDAC (available in the Arduino IDE libraries)

...et bonjour d'un autre français !

and these guys seem to be using the same thing as you : http://forum.aemodular.com/post/2980/thread

@frenchstudent, @zeferby

Is your MAX 5825 mounted on a breakout board or do you just have the SMD chip?

You basically need something like 

Wire.begin();
Wire.beginTransmission();
Wire.write(i2c_address, address, value); //the address will be the channel
Wire.endTransmission();

I have looked but can't find how the addressing works!

By the way, sorry guys about Japan. I am Welsh and I think the better team lost! 

@zeferby @pugwash

Thank you for the different link, i'll read it. On peut parler en français si nécessaire.

My MAX 5825 is on a breakout board.  I already write it : 

// Include Arduino Wire library for I2C
#include <Wire.h>

// Define Slave I2C Adress
#define SLAVE 9

void setup() {
// put your setup code here, to run once:
// Initialize I2C communictions as Master
Wire.begin();

//Setup serial monitor
Serial.begin(9600);
Serial.println("I2C MASTER DEMONSTRATION");
}

void loop() {
// put your main code here, to run repeatedly:
delay(50);
Serial.println("Write data to slave");

// Write a character to the Slave
Wire.beginTransmission(SLAVE);
Wire.write(0);
Wire.endTransmission();

Serial.println("Receive data");

Yeah i'm totally disappointed about the results. It's so sad because i thought that France will loose the cup against an other team and further in the championship.

@pugwash @frenchstudent

The Wire reference on Arduino's web is at https://www.arduino.cc/en/Reference/Wire  

Reading the datasheet, I think it may need to be something like :

byte byteArray[3];

byteArray[0] = max5828_command;
byteArray[1] = max5825_data_high;
byteArray[2] = max5825_data_low;

Wire.begin();
Wire.beginTransmission(max5825_i2c_address);
Wire.write(byteArray, 3);
Wire.endTransmission();

Maybe you could also try the variant which sends a Stop and releases the I2C bus :

Wire.endTransmission(true);

...and thanks @pugwash ? 

Also in the aemodular.com forum post above I read : "Ah! Found it! Page 25!!! "CODEn" sets the value for each DAC"

I took a look at the datasheet attached.

https://datasheets.maximintegrated.com/en/ds/MAX5823-MAX5825.pdf

I need to take at least a week to digest it! ? 

@ZeFerby

Thank you about the datasheet. I read it and i start to understand how the DAC works and the same for I²C adress. Nevertheless i don't understand how i can use it in the Arduino code. I think it comes from the fact i dont have a good level in electronics but i'm interesting in.

@pugwash

I understand that you register all your different information to use it later. But my main problem is to create the code on the Arduino...

@frenchstudent

I understand that you register all your different information to use it later. But my main problem is to create the code on the Arduino...

Well, I am afraid you are going to have to go through the same learning process as the rest of us.

The way I see it is, that I2C programming is the easy part. Having read the same datasheet as you guys, I am unable to decipher the addressing method of the MAX 5825.

@frenchstudent

I must add that hooking up a MAX5825 to an Arduino, as your first project, is very brave but not very wise. This is very much trying to run before you can walk.

I don't wish to sound cruel but nobody here is going to write the code for you.

As for the sample code I posted above, the writeToRegister() function or an adaptation, is fundamentally all you need to send data via I2C once the communication protocol has been initiated. And it doesn't matter where the data is coming from, array or sensor or anything else putting out digital values!

Posted by: @pugwash

Well, I am afraid you are going to have to go through the same learning process as the rest of us.

Well...i have bad news...it may take some time...

42 !