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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|------<-------'
| |
'-------'
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
37 lines
1.4 KiB
Plaintext
37 lines
1.4 KiB
Plaintext
What: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_invert
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Date: October 2016
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KernelVersion: 4.9
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Contact: Peter Rosin <peda@axentia.se>
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Description:
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The DAC is used to find the peak level of an alternating
|
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voltage input signal by a binary search using the output
|
|
of a comparator wired to an interrupt pin. Like so:
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|
_
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|
| \
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|
input +------>-------|+ \
|
|
| \
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|
.-------. | }---.
|
|
| | | / |
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|
| dac|-->--|- / |
|
|
| | |_/ |
|
|
| | |
|
|
| | |
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| irq|------<-------'
|
|
| |
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|
'-------'
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The boolean invert attribute (0/1) should be set when the
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input signal is centered around the maximum value of the
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dac instead of zero. The envelope detector will search
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from below in this case and will also invert the result.
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The edge/level of the interrupt is also switched to its
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opposite value.
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What: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_compare_interval
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Date: October 2016
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KernelVersion: 4.9
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Contact: Peter Rosin <peda@axentia.se>
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Description:
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Number of milliseconds to wait for the comparator in each
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step of the binary search for the input peak level. Needs
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to relate to the frequency of the input signal.
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