pcf85914
Driver for the pcf8591 8-bit a/d and d/a converter
Usage
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"
Overview
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>;
};
};
Releases
14 releases since FreeBSD 13.1-RELEASE; the text changed 3 times.