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Hello all,

I have finally acquired an FTDI Cable YEY!

Does anyone know what the command is to send data to the UEXT?

Thanks in advance



With an FTDI cable you want to use the COM2 serial port at the EXT connector. Look in the ebook for SerialPort usage.


I think the cable is wired correctly and I have deployed the ‘counting’ test from the book. It has taken the code but I am unable to read the data back at this point.

What I was after was the commands required to write a String to the FTDI and then read it back through the USB on a comport, to be sure it works.

Any ideas? :slight_smile:



Where are you plugging the ftdi cable? Into a pc or into the domino?


The FTDI cables USB side is connected to the PC and pin side is connected to the FEZ Dominos UEXT pins 1,3 and 4. Black, Yellow and Orange respectively. It seems to read as serial COM14 on the PC side, using MFDeploy.


UEXT is just a connector with some IOs.
FTDI is just a virtual serial cable

There is nothing special to do and no commands to send


Ok, so how do I send data to UEXT? :slight_smile:




But before you do anything take a look and read carefully the UART section in the free ebook in the Downloads page.

The FTDI’s interface is UART (Serial Port), then look for the UART pins on the UEXT and connect them to the FTDI. and connect the ground


Yup, I have them connected (as above).

I have deployed the counting program and am certain it is sending data to the correct port but I need to find a way to check this. I have fired up old Matlab and have created a serial port and seem to be able to connect to the virtual port, but I am unable to receive the data, aka integer values.

It may be that the data is being transferred in binary form, which would mean more work :] but I just wanted to confirm I have made a connection for now. Any data would be super to read from it.


Have you crossed the TX and RX line as I told you in the MATLAB post?


That’s why I suggested that you read carefully the UART section in the Ebook. there are many other stuff you need to configure to get the communication done correctly, like baudrate for example.


An easy way to count integers and output ASCII characters that a serial program can read is using a FOR loop, when i for instance goes from 0 to 9, and output i+‘0’ so you always output the correct character.


Hey guys,

Just a heads up… After setting the baud rate to be the same on both the output port on the FEZ and the input serial port on MATLAB, I am now able to read data flawlessly.

Thanks for all your help on this… I will add this on my other post too so it ties both problems together.

This is Frickin EZ :smiley: