1 What:		/sys/bus/iio/devices/iio:deviceX/in_altvoltageY_invert
2 Date:		October 2016
3 KernelVersion:	4.9
4 Contact:	Peter Rosin <peda@axentia.se>
5 Description:
6 		The DAC is used to find the peak level of an alternating
7 		voltage input signal by a binary search using the output
8 		of a comparator wired to an interrupt pin. Like so::
9 
10 		                           _
11 		                          | \
12 		     input +------>-------|+ \
13 		                          |   \
14 		            .-------.     |    }---.
15 		            |       |     |   /    |
16 		            |    dac|-->--|- /     |
17 		            |       |     |_/      |
18 		            |       |              |
19 		            |       |              |
20 		            |    irq|------<-------'
21 		            |       |
22 		            '-------'
23 
24 		The boolean invert attribute (0/1) should be set when the
25 		input signal is centered around the maximum value of the
26 		dac instead of zero. The envelope detector will search
27 		from below in this case and will also invert the result.
28 
29 		The edge/level of the interrupt is also switched to its
30 		opposite value.
31 
32 What:		/sys/bus/iio/devices/iio:deviceX/in_altvoltageY_compare_interval
33 Date:		October 2016
34 KernelVersion:	4.9
35 Contact:	Peter Rosin <peda@axentia.se>
36 Description:
37 		Number of milliseconds to wait for the comparator in each
38 		step of the binary search for the input peak level. Needs
39 		to relate to the frequency of the input signal.
40