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authorPeter Rosin2016-11-08 12:58:58 +0100
committerJonathan Cameron2016-11-13 13:07:17 +0000
commitb475f80b354a1915fda1b34070d712b825b60543 (patch)
tree02777a8c1349ace429f1dfa3e58e15661fed1eb5 /Documentation/ABI
parente778aa142ab0666fa8af789a3bbabfb3334e6ff5 (diff)
iio: envelope-detector: ADC driver based on a DAC and a comparator
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>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector36
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+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.