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GPIOPPS(4) NetBSD Kernel Interfaces Manual GPIOPPS(4)
Powered by man-cgi (2021-06-01).
Maintained for NetBSD
by Kimmo Suominen.
Based on man-cgi by Panagiotis Christias.
gpiopps -- install a PPS handler on GPIO pins
gpiopps* at gpio? offset 0 mask 0x1 flag 0x0
The gpiopps driver provides a 1PPS handler using the PPSAPI on one or two
The base pin number is specified in the kernel configuration file with
the offset locator. The mask should have 1 or 2 bits set, indicating
which pins offset from the base pin should be used (0 .. 31). Pin con-
figurations are discussed below.
The flag locator modifies the pin configuraiton:
0x01 The PPS ASSERT signal should be triggered on the negative
(falling) edge of the assert pin. The default is to trigger on
the positive (rising) edge of the pin.
0x02 By default, gpiopps will use double-edge triggering when only a
single pin is specified and the underlying GPIO hardware sup-
ports it. This flag disables the use of double-edge trigger-
If a single pin is specified, gpiopps uses double-edge triggering to sup-
port ASSERT and CLEAR PPS signals. If the underlying GPIO hardware does
not support double-edge triggering, or if this feature is diabled in the
flag locator, then only ASSERT will be signaled on the specified edge.
If two pins are specified, the first pin is used to trigger the ASSERT
signal and the second pin is used to trigger the CLEAR signal. The
ASSERT pin's trigger edge is specified by by the flag locator, and the
CLEAR pin triggers on the opposite edge. This allows ASSERT and CLEAR
signals to be triggered even if the underlying GPIO hardware does not
support double-edge triggering. In this scenario, both GPIO pins would
be connected in parallel to the device sending the 1PPS signals.
The offset, mask, and flag locators can also be specified when gpiopps is
attached at runtime using the GPIOATTACH ioctl(2) on the gpio(4) device.
gpio(4), drvctl(8), gpioctl(8)
The gpiopps driver first appeared in NetBSD 9.0.
The gpiopps driver was written by Brad Spencer <firstname.lastname@example.org>.
NetBSD 9.0 May 11, 2018 NetBSD 9.0