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PCF8574(4)		    Kernel Interfaces Manual		    PCF8574(4)

NAME
       pcf8574 -- driver for the PCF8574 8-bit I2C IO expander

SYNOPSIS
       To  compile  this  driver into the kernel, place	the following lines in
       your kernel configuration file:

	     device pcf8574
	     device gpio
	     device iicbus

       Alternatively, to load the driver as a module at	boot time,  place  the
       following line in loader.conf(5):

	     pcf8574_load="YES"

DESCRIPTION
       The  pcf8574  driver provides gpiobus(4)	control	over 8 GPIO pins.  The
       pins are	quasi-bidirectional.  Only low output can be actively  driven.
       High output is equivalent to input.

       On an FDT(4) based system the following properties must be set:

       compatible  Must	be set to "nxp,pcf8574".

       reg	   The I2C address of pcf8574.

       The DTS part for	a pcf8574 device usually looks like:

       / {

	       ...
	       pcf8574@27 {
		       compatible = "nxp,pcf8574";
		       reg = <0x27>;
	       };
       };

SEE ALSO
       fdt(4), gpiobus(4), iicbus(4)

HISTORY
       The  pcf8574  driver  and  this manual page was written by Andriy Gapon
       <avg@FreeBSD.org>.

BUGS
       The pcf8574 driver does not support the input change interrupt that the
       hardware	provides.

FreeBSD	14.3		       November	6, 2021			    PCF8574(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=pcf8574&sektion=4&manpath=FreeBSD+14.3-RELEASE+and+Ports>

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