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PCF8591(4) Kernel Interfaces Manual PCF8591(4) NAME pcf8591 -- driver for the PCF8591 8-bit A/D and D/A converter SYNOPSIS To compile this driver into the kernel, place the following lines in your kernel configuration file: device pcf8591 device iicbus Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): pcf8591_load="YES" DESCRIPTION The pcf8591 driver supports reading four inputs and setting one output over I2C. The hardware supports configuring the input lines as: • four single-ended inputs • three differential inputs (one input line is shared between all three inputs) • two single-ended inputs and one differential input • two differential inputs. The pcf8591 driver reports data via sysctl(8) entries in the device's node in the sysctl(8) tree: inputs.%d The input level of the corresponding input in steps between 0 and 255. Absolute voltage depends on an actual reference voltage. On an FDT(4) based system the following properties must be set: compatible Must be set to "nxp,pcf8591". reg The I2C address of pcf8591. It should be in the range from 0x40 to 0x4f (7-bit). The DTS part for a pcf8591 device usually looks like: / { ... pcf8591adc { compatible = "nxp,pcf8591"; reg = <0x48>; }; }; SEE ALSO fdt(4), iicbus(4), sysctl(8) HISTORY The pcf8591 driver and this manual page was written by Andriy Gapon <avg@FreeBSD.org>. BUGS The pcf8591 driver does not support changing the input configuration. All input lines are configured as single-ended inputs. The pcf8591 driver does not support setting the output. It is always disabled (tri-state). FreeBSD 15.0 November 6, 2021 PCF8591(4)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | BUGS
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