nakchak,

thanks for your suggestion. I do not need the external reset, so I have not implemented that. 

But I just made some significant progress:
The problem seems to be related to the software, at least in some way.

It seems that there is some interference with the Serial Port, defined as:
[font="'courier new', courier, monospace;"]ReadPort = new SerialPort(SerialPorts.COM1, 9600, Parity.None, 8, StopBits.One);[/font]

If I don't use that port, then the software reset seems to work.

I am getting a bit further now. It seems that VS Studio can deploy the application via USB to the PCB. Immediately after the deployment the PCB should reboot in order to get into Debug mode and let itself debug from Visual Studio. This doesn't work. I suspect it is something I am not doing correctly in the hardware. Does anybody have an idea what particular hardware requirements are needed for that?

Thanks

I have built a proprietary Netduino2-based PCB, running the STM32F205RGT6 processor.

V4.2 firmware loaded correctly, the board is recognized as Netduino and I was able to load the first test program from Visual Studio.

But now I cannot load any other program anymore, I get the infamous "Unable to communicate with device" message.

The PCB doesn't contain any circuitry to reset the board when Visual Studio starts communicating with the board. Am I missing something?

Does anybody know if there is an additional handshake or reset taking place when uploading programs via USB than just USB communication?

OK, I think I resolved it myself.

For the Netduino 2 the repeated start bit feature seems to work without needing this workaround, so standard features from the  I2CDevice.I2CTransaction class can be used directly.

OK, I got it working on the Netduino 2:

It seems that the repeated start bit is handled in the Netduino 2, hence the [color=rgb(90,90,90);font-family:helvetica, arial, sans-serif;font-size:13px;background-color:rgb(234,248,226);] [/color]special I2C methods (which seem not to work with the Netduino 2) are not required for the Netduino 2.

Hence, you can use the code that I have originally posted - it does work for me - I can now read all the registers correctly.

Something like the code below should work for reading x, y and z position to an accuracy of one byte, only using the MSB registers. If you need higher resolution you will also need to consider the LSB registers. 

I have no success using this code on Netduino 2.

While it works fine for the Netduino 1, running it on Netduino 2 (firmware V 4.2.2.2), throws an exception because [color=#ff0000;]fieldInfo[/color] remains Null after the line:

[font="'courier new', courier, monospace;"][color=rgb(102,0,102);]FieldInfo[/color] [color=#ff0000;]fieldInfo[/color] [/font][color=rgb(102,102,0);]=[/color] readTransactionType[color=rgb(102,102,0);].[/color][color=rgb(102,0,102);]GetField[/color][color=rgb(102,102,0);]([/color][color=rgb(0,136,0);]"Custom_InternalAddress"[/color][color=rgb(102,102,0);],[/color] [color=rgb(102,0,102);]BindingFlags[/color][color=rgb(102,102,0);].[/color][color=rgb(102,0,102);]NonPublic[/color] [color=rgb(102,102,0);]|[/color] [color=rgb(102,0,102);]BindingFlags[/color][color=rgb(102,102,0);].[/color][color=rgb(102,0,102);]Instance[/color][color=rgb(102,102,0);])[/color][font="'courier new', courier, monospace;"];[/font]

Any suggestion?

Thanks - Thomas

cmelk75, sorry, I have not noticed your question earlier.

But it happens that I am trying to port my application to a Netduino 2 - and I cannot get it work.

There are various threads about problems with I2C on Netdiuino 2.

So far I have tried:

- Decrease the value of the pull-up resistors to 1k

- Upgrade firmware to 4.2.2.2

Neither has helped :-(

CW2, I have updated the Firmware to 4.2 and used the recommended way to address the I2C registers in read mode - and it works like a charm! Thanks very much for your great help - Happy New Year!

Thanks so much for your education - it will take me a while to update the firmware - it will be the first time for me doing it.  I will keep you posted.

I may have an older version:  4.1.0.6, may this be the issue?

CW2, thanks very much for the quick response, I very much appreciate. 

I have tried this before, but did not succeed to get it running, I always get a Null Value for fieldInfo:

I have attached a Triple Axis Accelerometer Breakout - MMA8452Q from Sparkfun, https://www.sparkfun.../products/10955 to a Netduino board.
The physical connection seems to work, as well as writing and reading - the only problem, I cannot set the register to read from.