NitinSontakke

@scardinale, You are a STAR!

I copied and executed the I2C Scanner and it gave me Int32 address 112, which i right shifted by 1 and used and it WORKED for my other project!

Not sure how on earth one (read, novice like me!) would think of running a scanner to determine an address of a device and then use it.

Anyway, I thank you very much for taking away the biggest stumbling block in my journey towards ambitious home automation project.

Thanks, again!

Hello,

Right shifting 0x40 by 1 bit gives me 0x20 (decimal 32). Now it makes sense to me why this value is being used in all the code i see here. While it was step in right direction, unfortunately, it hasn't help resolve the issue.

Shown below is the code i copied from this thread, added the "magic code block" right at the beginning and changed the address to 0x20.

I commented out the "read" transaction because data-sheet mentions that this address is for "write" transaction.

The output is "not found" three times.

PCF8574 -> N2P connections are as follows:

VCC -> 5V - 10k pull-up registered applied

INT -> Nothing

SCL -> SCL

SDA -> SDA

A0, A1, A2 -> Ground

I had taken the photo of assembly but i am facing problem uploading it here.

    public static void Main()
    {
      using (OutputPort i2cPort = new OutputPort(Pins.GPIO_PIN_SDA, true))
      {
        i2cPort.Write(false);
        Thread.Sleep(100);
      }

      I2CDevice.Configuration config = new I2CDevice.Configuration(0x20, 100);
      I2CDevice I2C_Bus = new I2CDevice(config);

      I2CDevice.I2CTransaction[] transactions;
      transactions = new I2CDevice.I2CTransaction[1];

      transactions[0] = I2CDevice.CreateWriteTransaction(new byte[0xff]);
      //transactions[1] = I2CDevice.CreateReadTransaction(new byte[1]);

      for (Int32 i = 0; i < 3; i++)
      {
        Int32 result = I2C_Bus.Execute(transactions, 1000);

        if (result > 0)
        {
          Debug.Print("found");
        }
        else
        {
          Debug.Print("not found");
        }
      }
    }

Thanks! Will try and update.

@hareega,

If you could care to mention the device / chip you are using, please!

I am using NP2 and NETMF 4.3 and....

I have been struggling to get i2c working with PCF8574 and PCF8575 over days now with no luck so far and any help from anyone on forum is hugely appreciated.

I using classes generously provided by NooM

The data-sheet indicates address 0x40, which i tried and also tried the default of 0x20.

Pins -> Absolutely nothing special. Pull-up registers are applied as am working on break-out board.

Please help!

Hello,

Apologies to rekindle this thread. I am struggling to have PCF8575 16bit io expander (Sparkfun) working and was wondering if GrZeCh has managed successfully implement it, could please be helpful to share the code.

Thanks in advance.