Documentation/usb/misc_usbsevseg.txt

   1 USB 7-Segment Numeric Display
   2 Manufactured by Delcom Engineering
   3
   4 Device Information
   5 ------------------
   6 USB VENDOR_ID   0x0fc5
   7 USB PRODUCT_ID  0x1227
   8 Both the 6 character and 8 character displays have PRODUCT_ID,
   9 and according to Delcom Engineering no queryable information
  10 can be obtained from the device to tell them apart.
  11
  12 Device Modes
  13 ------------
  14 By default, the driver assumes the display is only 6 characters
  15 The mode for 6 characters is:
  16         MSB 0x06; LSB 0x3f
  17 For the 8 character display:
  18         MSB 0x08; LSB 0xff
  19 The device can accept "text" either in raw, hex, or ascii textmode.
  20 raw controls each segment manually,
  21 hex expects a value between 0-15 per character,
  22 ascii expects a value between '0'-'9' and 'A'-'F'.
  23 The default is ascii.
  24
  25 Device Operation
  26 ----------------
  27 1.      Turn on the device:
  28         echo 1 > /sys/bus/usb/.../powered
  29 2.      Set the device's mode:
  30         echo $mode_msb > /sys/bus/usb/.../mode_msb
  31         echo $mode_lsb > /sys/bus/usb/.../mode_lsb
  32 3.      Set the textmode:
  33         echo $textmode > /sys/bus/usb/.../textmode
  34 4.      set the text (for example):
  35         echo "123ABC" > /sys/bus/usb/.../text (ascii)
  36         echo "A1B2" > /sys/bus/usb/.../text (ascii)
  37         echo -ne "\x01\x02\x03" > /sys/bus/usb/.../text (hex)
  38 5.      Set the decimal places.
  39         The device has either 6 or 8 decimal points.
  40         to set the nth decimal place calculate 10 ** n
  41         and echo it in to /sys/bus/usb/.../decimals
  42         To set multiple decimals points sum up each power.
  43         For example, to set the 0th and 3rd decimal place
  44         echo 1001 > /sys/bus/usb/.../decimals
  45
  46