Hi guys I need some help with I2C and Netduino plus 1.
Actually I'm using the A4-A5 Pins to try to communicate with an Adafruit servo shield but just noticied something that's getting me totally confused -I have to say I'm totally new on this but.. seems no sense-
Actually the Shield should be at the address 0x40 as documentation says.
Running the following test code I got confusing outputs:
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
namespace NetduinoPlusApplication2
{
public class Program
{
static I2CDevice.Configuration _i2cdevice;
public static void Main()
{
try
{
Debug.Print("Trying addr: " + 0x38+ "------------------------------------");
_i2cdevice = new I2CDevice.Configuration(0x38, 400);
I2CDevice MyI2C = new I2CDevice(_i2cdevice);
I2CDevice.I2CTransaction[] xActions = new I2CDevice.I2CTransaction[2];
byte[] RegisterNum = new byte[1] { 2 };
xActions[0] = I2CDevice.CreateWriteTransaction(RegisterNum);
byte[] RegisterValue = new byte[1];
xActions[1] = I2CDevice.CreateReadTransaction(RegisterValue);
if (MyI2C.Execute(xActions, 1000) == 0)
{
Debug.Print("Failed to perform I2C transaction");
}
else
{
Debug.Print("Register value: " + RegisterValue[0].ToString());
}
}
catch
{
Debug.Print("EXCEPTION " );
}
}
}
}
Notice I'm trying to setup it wrong, I2CDevice.Configuration(0x38, 400); ..but the output:
Trying addr: 56------------------------------------
Register value: 0
The thread '<No Name>' (0x1) has exited with code 0 (0x0).
Done.
Ok, Trying the 0x40 (64)
Trying addr: 64------------------------------------
Register value: 0
The thread '<No Name>' (0x1) has exited with code 0 (0x0).
Done.
and here comes the fun...I unplug the a4 and a5 and ..
First time I try: -It should say it failed as it does, so I guess this is right -
Trying addr: 64------------------------------------
Failed to perform I2C transaction
The thread '<No Name>' (0x1) has exited with code 0 (0x0).
Done.
Ok ..now let's try again -nothing is plugged-
The thread '<No Name>' (0x2) has exited with code 0 (0x0).
Trying addr: 64------------------------------------
Register value: 0
The thread '<No Name>' (0x1) has exited with code 0 (0x0).
Done.
How's this possible? first it reads something for an non present address, second time it reads from the 0x40, when it's unplugged it says it failed as expected the first time, but the second time says it was fine... I'm totally confused
Any idea on this? Thank you very much in advance
