[SLOVED] Arduino Mega - SMBus with a LTC1427 help

Projects Networking, Protocols, and Devices
1

Hello Folks

I'm very new to the whole firmware/software world (I'm hardware electronics engineer) and I'm trying to get a slave device called LTC1427 which is a 10bit current DAC which will be used to vagary the voltage output of a buck boost. This DAC can only receive.

Below is the code that I started to write and got some data coming but I believe the Wire.write commands aren't working correctly. I suspect I'm doing something very silly.

When I say the wire.write commands aren't working correctly what i mean is no matter what hex value I put into the variables the data coming out doesn't change. I'm using an oscilloscope to view that data and clock.

The Wire.beginTransmission does work as I can change these variables and see the difference on the scope.

//////////////////////////////////////////////////////////////////////////////////////////////////////////////
#include <Wire.h>

void setup() // run once, when the sketch starts
{
Wire.begin();
Serial.begin(115200);

Serial.println("All work and no play make Stephen a dull boy!"); // prints hello with ending line break
LTC1427_TX();
}

void LTC1427_TX()
{
byte ADD = 0x2D;
byte value1 = 0x10;
byte value2 = 0xAA;

Wire.beginTransmission(ADD);
Wire.write(0,1); //WR
Wire.write(0,1); //ACK
Wire.write(value1);//Command
Wire.write(0,1); //ACK
Wire.write(value2);//Data TX
Wire.write(0,1); //ACK
Wire.endTransmission();
}

void loop() // run over and over again
{
// do nothing!
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////

LTC1427.pdf (206 KB)

2

Solved my problem, Turns out I was been silly with the Oscilloscope. Below is the code for a saw tooth wave.

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include <Wire.h>

void setup()
{
Wire.begin();
Serial.begin(115200);
}

byte val = 0;
byte valHi = 0;

void loop()
{
Wire.beginTransmission(0x2D); //Address when AD0 & AD1 are low

Wire.write(valHi);
Wire.write(val);
Wire.endTransmission();

val++;
if(val == 255)
{
val = 0;
valHi++;
}
if(valHi==4)
{
valHi=0;
}
Serial.print(valHi);
Serial.print(" ");
Serial.print(val);
Serial.println();
delay(5);
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////