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Documentation / usb / misc_usbsevseg.txt




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Based on kernel version 3.16. Page generated on 2014-08-06 21:41 EST.

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	
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