RESOLVED: No serial device in listening mode (OS X 10.9.2 Mavericks)


EDIT: This somehow resolved itself, immediately after posting this topic! Whoever haxor3d my b4s3 and fixed it so quickly, thank you! :stuck_out_tongue: (More seriously, it may have had something to do with quitting VMWare Fusion. Hmmm.)

I’ve got a Sparkcore connected to my iMac via USB and I’ve put it in listening mode – LED flashing blue.

My understanding it that this should present a USB serial device, something like /dev/cu.usbmodemNNNNN. But this is not happening.

Is there any particular USB serial “driver” or kernel extension required to be installed? (I assume not.) If not, what kernel extension should be in place to enable the Sparkcore’s flavor of USB serial?

I put that lat question in bold because I have been playing around with my system, enabling and disabling portions of FTDI based USB drivers, for unrelated reasons. I might have messed something up. Knowing which kext should be working for the Sparkcore might help me find a solution, here.


I have the same issue, no serial port is detected while connecting my spark core (MAC OSX 10.9.4).
Is there a solution to that issue?

Hi @rrobinet1

I have a a Mac and on thing you should know is that the device does not appear on the Mac until you do Serial.begin(baudRate); on the core, typically in setup(). Before that, there is no device. I use CoolTerm but there are lots of alternatives including the Spark CLI.

Thanks @bko,

Indeed it works while setting the serial interface (and connect for instance with CoolTerm).
This is my first experience with the Spark Core (after years of playing with Arduino).
I was told since years to read the f… manual before anything.
This is what I am doing. If you look at the documentation (see extract below … Connect over USB).
So either the doc is wrong (and should be reviewed) or I a was missing a step while testing this connectivity.


You can also connect the Spark Core to your Wi-Fi network over USB by communicating through Serial.
NOTE: This only works when the Spark Core is in Listening Mode (i.e. RGB led is blinking blue).

For Mac users, either CoolTerm or screen work… (On OS X, the command line invocation might look something like screen /dev/cu.usbmodem1411 9600. … When the Spark Core is in Listening Mode, open a serial port over USB using the standard settings, which should be:
Baudrate: 9600
Data Bits: 8
Parity: none
Stop Bits: 1

Hi @rrobinet1

There are two different things going on here:

  • When you need to configure the Spark core’s WiFi credentials, the core needs to be in “listening mode” which has a blinking blue LED. In listening mode, the core listens for WiFi Smart Config packets over the air but also is looking for USB serial characters at 9600 baud. If you connect to USB serial in listening mode, there is a little input form where you can type your WiFi mode, SSID and password. None of your code is running during this process, only built-in code.

  • When you are using the serial port in your code, the serial device does not get mounted on the host computer until your code does Serial.begin(baudRate);. On Windows there is sometimes a problem where you might even want to loop in setup() waiting for the user to type a character so you can start the port properly.

So the doc is describing the first point where you are setting up the core. Hope this helps explain the difference!

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Thanks again for your clear answer.
I just started to plat with the Spark core and I still Arduino minded expecting a Serial connection as soon the device is connected via USB.

Indeed @rrobinet1. I guess you’ve realised why the difference. It’s because the Spark core implements its various USB devices on the main MCU chip itself, which contains USB interface hardware internally, whereas the Arduino has an outboard, dedicated USB serial device chip that fires up as soon as power is applied.

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