1b475f80bSPeter RosinWhat: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_invert 2b475f80bSPeter RosinDate: October 2016 3b475f80bSPeter RosinKernelVersion: 4.9 4b475f80bSPeter RosinContact: Peter Rosin <peda@axentia.se> 5b475f80bSPeter RosinDescription: 6b475f80bSPeter Rosin The DAC is used to find the peak level of an alternating 7b475f80bSPeter Rosin voltage input signal by a binary search using the output 8b475f80bSPeter Rosin of a comparator wired to an interrupt pin. Like so: 9b475f80bSPeter Rosin _ 10b475f80bSPeter Rosin | \ 11b475f80bSPeter Rosin input +------>-------|+ \ 12b475f80bSPeter Rosin | \ 13b475f80bSPeter Rosin .-------. | }---. 14b475f80bSPeter Rosin | | | / | 15b475f80bSPeter Rosin | dac|-->--|- / | 16b475f80bSPeter Rosin | | |_/ | 17b475f80bSPeter Rosin | | | 18b475f80bSPeter Rosin | | | 19b475f80bSPeter Rosin | irq|------<-------' 20b475f80bSPeter Rosin | | 21b475f80bSPeter Rosin '-------' 22b475f80bSPeter Rosin The boolean invert attribute (0/1) should be set when the 23b475f80bSPeter Rosin input signal is centered around the maximum value of the 24b475f80bSPeter Rosin dac instead of zero. The envelope detector will search 25b475f80bSPeter Rosin from below in this case and will also invert the result. 26b475f80bSPeter Rosin The edge/level of the interrupt is also switched to its 27b475f80bSPeter Rosin opposite value. 28b475f80bSPeter Rosin 29b475f80bSPeter RosinWhat: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_compare_interval 30b475f80bSPeter RosinDate: October 2016 31b475f80bSPeter RosinKernelVersion: 4.9 32b475f80bSPeter RosinContact: Peter Rosin <peda@axentia.se> 33b475f80bSPeter RosinDescription: 34b475f80bSPeter Rosin Number of milliseconds to wait for the comparator in each 35b475f80bSPeter Rosin step of the binary search for the input peak level. Needs 36b475f80bSPeter Rosin to relate to the frequency of the input signal. 37