A-Star device /dev/tty.usb* doesn't show up in MacOS lab

Hi,

I have a Mac lab full of students with A-Star 32u4 Prime LV boards and we can’t get them to work. They’re working fine on our Mac, Windows, and Linux laptops so I suspect it’s something to do with our lab configuration. When I plug in the board, no new devices are added to /dev (and there are no usbmodem anythings in there). Any ideas?

The model machines are: iMac (Retina 5K, 27-inch, Late 2014)
MacOSX Yosemite 10.10.5 (14F27)

Thanks for any help,
Rob

Hello, Rob.

I am sorry you are having trouble with the A-Star 32U4 Prime LV in your Mac lab. You could try running the following commands on a lab computer to get more information about how the computer has detected the A-Star:

ioreg -p IOUSB -w 0
ioreg -p IOUSB -l -w 0
sudo dmesg

Here is a shell session showing the results that I see when I run those commands on a Mac here:

$ ioreg -p IOUSB -w 0
+-o Root  <class IORegistryEntry, id 0x100000100, retain 10>
  +-o EHCI Root Hub Simulation@1D,7  <class IOUSBRootHubDevice, id 0x100000214, registered, matched, active, busy 0 (11 ms), retain 11>
  | +-o HubDevice@fd100000  <class IOUSBHubDevice, id 0x100000262, registered, matched, active, busy 0 (7 ms), retain 15>
  |   +-o IR Receiver@fd110000  <class IOUSBDevice, id 0x10000026c, registered, matched, active, busy 0 (87 ms), retain 10>
  |   +-o USB Hub 2.0@fd130000  <class IOUSBHubDevice, id 0x100000287, registered, matched, active, busy 0 (3 ms), retain 13>
  |   | +-o Dell USB Entry Keyboard@fd132000  <class IOUSBDevice, id 0x100000295, registered, matched, active, busy 0 (65 ms), retain 10>
  |   | +-o USB Optical Mouse@fd134000  <class IOUSBDevice, id 0x10000029f, registered, matched, active, busy 0 (82 ms), retain 10>
  |   +-o Pololu A-Star 32U4@fd120000  <class IOUSBDevice, id 0x1000004bc, registered, matched, active, busy 0 (65 ms), retain 12>
  +-o EHCI Root Hub Simulation@1A,7  <class IOUSBRootHubDevice, id 0x100000236, registered, matched, active, busy 0 (6 ms), retain 11>
    +-o HubDevice@fa100000  <class IOUSBHubDevice, id 0x100000266, registered, matched, active, busy 0 (6 ms), retain 11>
      +-o BRCM20702 Hub@fa110000  <class IOUSBHubDevice, id 0x100000282, registered, matched, active, busy 0 (3 ms), retain 11>
        +-o Bluetooth USB Host Controller@fa113000  <class IOUSBDevice, id 0x10000029e, registered, matched, active, busy 0 (41 ms), retain 12>

$ ioreg -p IOUSB -l -w 0
...
  |   +-o Pololu A-Star 32U4@fd120000  <class IOUSBDevice, id 0x1000004bc, registered, matched, active, busy 0 (65 ms), retain 12>
  |       {
  |         "sessionID" = 553615357855
  |         "idProduct" = 8960
  |         "bNumConfigurations" = 1
  |         "iManufacturer" = 1
  |         "bcdDevice" = 256
  |         "Bus Power Available" = 250
  |         "bMaxPacketSize0" = 64
  |         "USB Product Name" = "Pololu A-Star 32U4"
  |         "iProduct" = 2
  |         "iSerialNumber" = 0
  |         "USB Address" = 7
  |         "IOUserClientClass" = "IOUSBDeviceUserClientV2"
  |         "bDeviceSubClass" = 0
  |         "bDeviceClass" = 2
  |         "bcdUSB" = 512
  |         "locationID" = 18446744073660399616
  |         "PortNum" = 2
  |         "IOCFPlugInTypes" = {"9dc7b780-9ec0-11d4-a54f-000a27052861"="IOUSBFamily.kext/Contents/PlugIns/IOUSBLib.bundle"}
  |         "bDeviceProtocol" = 0
  |         "USB Vendor Name" = "Pololu Corporation"
  |         "Device Speed" = 1
  |         "idVendor" = 8187
  |         "Requested Power" = 250
  |         "IOGeneralInterest" = "IOCommand is not serializable"
  |         "Low Power Displayed" = No
  |       }
...

$ sudo dmesg
...
         0 [Level 5] [com.apple.message.domain com.apple.commssw.cdc.device] [com.apple.message.signature AppleUSBCDCACMData] [com.apple.message.signature2 0x1FFB] [com.apple.message.signature3 0x2300]
AppleUSBCDCACMData: Version number - 4.3.2b1, Input buffers 8, Output buffers 16
AppleUSBCDC: Version number - 4.3.2b1

$ ls /dev/*modem*
/dev/cu.usbmodemfd121	/dev/tty.usbmodemfd121

There might be settings on the lab computers that restrict what types of USB devices are allowed, or disable certain USB ports. I do not know where you would look for such settings, but you might try asking your system administrator if you have one.

–David

The problem is related to the security in the lab. Access to the Network system pref pane is disabled and that’s the cause.