CODEWITHSUNDEEP
macosusbtty
Majenko
Majenko

Reputation: 1840

Getting USB data for OS X /dev/tty.* entry

I am trying to (programatically in Java, though running external scripts is a possibility) get the USB idProduct, idVendor and ideally the string descriptors for the manufacturer and product for a USB device.

The device has (and it is all I am provided with in the beginning) a /dev/tty.usbmodem entry, and I need some way to reliably map that back to the USB information, but I can't find anything that relates one to the other (or rather I don't know where to look).

The device in question has the /dev entry of:

crw-rw-rw-  1 root  wheel   10,   2 18 Jul 15:08 /dev/tty.usbmodem9f31

system_profiler gives me the following USB information for the device:

<dict>
    <key>_name</key>
    <string>Stk500v2</string>
    <key>a_product_id</key>
    <string>0xa662</string>
    <key>b_vendor_id</key>
    <string>0x0403  (Future Technology Devices International Limited)</string>
    <key>c_bcd_device</key>
    <string> 1.80</string>
    <key>e_device_speed</key>
    <string>full_speed</string>
    <key>f_manufacturer</key>
    <string>www.cpustick.com</string>
    <key>g_location_id</key>
    <string>0x9f300000</string>
    <key>h_bus_power</key>
    <string>500</string>
    <key>j_bus_power_used</key>
    <string>500</string>
</dict>

I can see the prefix of 0x9f3 for the g_location_id matching the start of the dev entry's suffix of 9f31, but I don't know a) how reliable that would be, and b) what the "1" would represent at the end, and how that would be affected by having multiple of the same device on the same bus, and how you would differentiate between them.

I have other devices I need to do this with as well, and they don't all follow the same naming rules. One of them uses the USB serial number field for the suffix. Other potential ones (that I don't have control over at all) could do it differently again I guess.

So basically I need some way of mapping the textual device name /dev/tty.whatever to a physical USB device entry that I can then pull the data I need from. On Linux I do it by traversing the /sys tree from /sys/class/tty through to /sys/devices/pci...blahblah/usb[x]/wherever but I can find no similar facility on OS X.

Upvotes: 0

Views: 1601

Answers (1)

David Grayson
David Grayson

Reputation: 87486

You can use IOKit to get the USB vendor ID and product ID of a serial port on Mac OS X.

Also, there is a library called libserialport that you could use:

http://sigrok.org/wiki/Libserialport

Upvotes: 2

Related Questions