forked from Minki/linux
37 lines
1.4 KiB
Plaintext
37 lines
1.4 KiB
Plaintext
|
What: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_invert
|
||
|
|
Date: October 2016
|
||
|
|
KernelVersion: 4.9
|
||
|
|
Contact: Peter Rosin <peda@axentia.se>
|
||
|
|
Description:
|
||
|
|
The DAC is used to find the peak level of an alternating
|
||
|
|
voltage input signal by a binary search using the output
|
||
|
|
of a comparator wired to an interrupt pin. Like so:
|
||
|
|
_
|
||
|
|
| \
|
||
|
|
input +------>-------|+ \
|
||
|
|
| \
|
||
|
|
.-------. | }---.
|
||
|
|
| | | / |
|
||
|
|
| dac|-->--|- / |
|
||
|
|
| | |_/ |
|
||
|
|
| | |
|
||
|
|
| | |
|
||
|
|
| irq|------<-------'
|
||
|
|
| |
|
||
|
|
'-------'
|
||
|
|
The boolean invert attribute (0/1) should be set when the
|
||
|
|
input signal is centered around the maximum value of the
|
||
|
|
dac instead of zero. The envelope detector will search
|
||
|
|
from below in this case and will also invert the result.
|
||
|
|
The edge/level of the interrupt is also switched to its
|
||
|
|
opposite value.
|
||
|
|
|
||
|
|
What: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_compare_interval
|
||
|
|
Date: October 2016
|
||
|
|
KernelVersion: 4.9
|
||
|
|
Contact: Peter Rosin <peda@axentia.se>
|
||
|
|
Description:
|
||
|
|
Number of milliseconds to wait for the comparator in each
|
||
|
|
step of the binary search for the input peak level. Needs
|
||
|
|
to relate to the frequency of the input signal.
|