{{fbdoc item="title" value="gpiopins.bi digital GPIO interface"}}----
A small portable-facing interface to target GPIO character devices.

{{fbdoc item="syntax"}}
%%(freebasic)
#include once "gpiopins.bi"
%%

{{fbdoc item="desc"}}
	##GpioPinOpen(pin)## opens the NuttX device named ##/dev/gpioN##.  ##GpioPinOpenDevice(device)## opens an explicit device path.  Both return a non-negative handle or ##-1## on failure.

	##GpioPinRead(handle)## returns ##GPIOPIN_LOW##, ##GPIOPIN_HIGH##, or ##-1##.  ##GpioPinWrite(handle, value)## and ##GpioPinClose(handle)## return zero on success and ##-1## on failure.  ##GpioPinGetType## and ##GpioPinSetType## query or request one of the ##GPIOPIN_*## input, output, open-drain, or interrupt modes declared by the header.

	The current hardware implementation is the NuttX GPIO character-device backend.  Other targets export predictable unsupported-operation stubs so a portable source can link.  Hosted targets report ##ENOSYS## through ##errno##; Windows CE reports ##ERROR_CALL_NOT_IMPLEMENTED## through ##GetLastError##.  Device numbering, pin mux, electrical limits, and interrupt registration remain board responsibilities.

{{fbdoc item="ex"}}
%%(freebasic)
#include once "gpiopins.bi"

dim as integer pin = GpioPinOpen( 0 )
if pin < 0 then
	print "GPIO 0 is unavailable"
	end 1
end if

if GpioPinSetType( pin, GPIOPIN_OUTPUT ) = 0 then
	GpioPinWrite( pin, GPIOPIN_HIGH )
end if

GpioPinClose( pin )
%%

{{fbdoc item="ver"}}
	- Since fbc 1.20.2

{{fbdoc item="see"}}
	- ##[[DevNuttX|NuttX and RISC-V board workflow]]##
	- ##[[KeyPgDdfbnuttx|__FB_NUTTX__]]##

{{fbdoc item="back" value="CatPgProgrammer|Programmer's Guide"}}