:orphan:
.. raw:: html
.. dtcompatible:: espressif,esp32-pcnt
.. _dtbinding_espressif_esp32_pcnt:
espressif,esp32-pcnt
####################
Vendor: :ref:`Espressif Systems `
Description
***********
.. code-block:: none
Espressif's Pulse Counter Mode (PCNT) controller Node
The pulse counter module is designed to count the number of
rising and/or falling edges of an input signal.
The ESP32's PCNT module has 8 independent counting “units” numbered from 0 to 7.
ESP32S2 and ESP32S3 have 4 independent counting “units” numbered from 0 to 3.
Each pulse counter unit has a 16-bit signed counter register.
Each unit has two independent channel: ch0 and ch1 that can be configured
to either increment or decrement the counter.
Each channel has two inputs: a signal input that accepts signal edges
to be detected, as well as a control input that can be used to enable
or disable the signal input.
Each pulse counter unit also features a filter on each of the four inputs,
adding the option to ignore short glitches in the signals.
By combining the usage of both signal and control inputs, a PCNT unit can
act as a quadrature decoder.
Example: Use PCNT to read a rotary-enconder
The mapping between signal and control input and the pin is done through pinctrl:
&pinctrl {
pcnt_default: pcnt_default {
group1 {
pinmux = ,
;
bias-pull-up;
};
};
};
Note: Check espressif,esp32-pinctrl.yaml for complete documentation regarding pinctrl.
Use the PCNT node to configure the module:
&pcnt {
pinctrl-0 = <&pcnt_default>;
pinctrl-names = "default";
status = "okay";
#address-cells = <1>;
#size-cells = <0>;
unit0@0 {
reg = <0>;
#address-cells = <1>;
#size-cells = <0>;
filter = <100>;
channelA@0 {
reg = <0>;
sig-pos-mode = <2>;
sig-neg-mode = <1>;
ctrl-h-mode = <0>;
ctrl-l-mode = <1>;
};
};
};
Properties
**********
Top level properties
====================
These property descriptions apply to "espressif,esp32-pcnt"
nodes themselves. This page also describes child node
properties in the following sections.
.. tabs::
.. group-tab:: Node specific properties
Properties not inherited from the base binding file.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``friendly-name``
- ``string``
- .. code-block:: none
Human readable string describing the sensor. It can be used to
distinguish multiple instances of the same model (e.g., lid accelerometer
vs. base accelerometer in a laptop) to a host operating system.
This property is defined in the Generic Sensor Property Usages of the HID
Usage Tables specification
(https://usb.org/sites/default/files/hut1_3_0.pdf, section 22.5).
* - ``pinctrl-0``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the first state. Content is specific to the
selected pin controller driver implementation.
* - ``pinctrl-1``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the second state. See pinctrl-0.
* - ``pinctrl-2``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the third state. See pinctrl-0.
* - ``pinctrl-3``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the fourth state. See pinctrl-0.
* - ``pinctrl-4``
- ``phandles``
- .. code-block:: none
Pin configuration/s for the fifth state. See pinctrl-0.
* - ``pinctrl-names``
- ``string-array``
- .. code-block:: none
Names for the provided states. The number of names needs to match the
number of states.
.. group-tab:: Deprecated node specific properties
Deprecated properties not inherited from the base binding file.
(None)
.. group-tab:: Base properties
Properties inherited from the base binding file, which defines
common properties that may be set on many nodes. Not all of these
may apply to the "espressif,esp32-pcnt" compatible.
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``status``
- ``string``
- .. code-block:: none
indicates the operational status of a device
Legal values: ``'ok'``, ``'okay'``, ``'disabled'``, ``'reserved'``, ``'fail'``, ``'fail-sss'``
See :ref:`dt-important-props` for more information.
* - ``compatible``
- ``string-array``
- .. code-block:: none
compatible strings
This property is **required**.
See :ref:`dt-important-props` for more information.
* - ``reg``
- ``array``
- .. code-block:: none
register space
See :ref:`dt-important-props` for more information.
* - ``reg-names``
- ``string-array``
- .. code-block:: none
name of each register space
* - ``interrupts``
- ``array``
- .. code-block:: none
interrupts for device
See :ref:`dt-important-props` for more information.
* - ``interrupts-extended``
- ``compound``
- .. code-block:: none
extended interrupt specifier for device
* - ``interrupt-names``
- ``string-array``
- .. code-block:: none
name of each interrupt
* - ``interrupt-parent``
- ``phandle``
- .. code-block:: none
phandle to interrupt controller node
* - ``label``
- ``string``
- .. code-block:: none
Human readable string describing the device (used as device_get_binding() argument)
See :ref:`dt-important-props` for more information.
This property is **deprecated**.
* - ``clocks``
- ``phandle-array``
- .. code-block:: none
Clock gate information
* - ``clock-names``
- ``string-array``
- .. code-block:: none
name of each clock
* - ``#address-cells``
- ``int``
- .. code-block:: none
number of address cells in reg property
* - ``#size-cells``
- ``int``
- .. code-block:: none
number of size cells in reg property
* - ``dmas``
- ``phandle-array``
- .. code-block:: none
DMA channels specifiers
* - ``dma-names``
- ``string-array``
- .. code-block:: none
Provided names of DMA channel specifiers
* - ``io-channels``
- ``phandle-array``
- .. code-block:: none
IO channels specifiers
* - ``io-channel-names``
- ``string-array``
- .. code-block:: none
Provided names of IO channel specifiers
* - ``mboxes``
- ``phandle-array``
- .. code-block:: none
mailbox / IPM channels specifiers
* - ``mbox-names``
- ``string-array``
- .. code-block:: none
Provided names of mailbox / IPM channel specifiers
* - ``wakeup-source``
- ``boolean``
- .. code-block:: none
Property to identify that a device can be used as wake up source.
When this property is provided a specific flag is set into the
device that tells the system that the device is capable of
wake up the system.
Wake up capable devices are disabled (interruptions will not wake up
the system) by default but they can be enabled at runtime if necessary.
* - ``power-domain``
- ``phandle``
- .. code-block:: none
Power domain the device belongs to.
The device will be notified when the power domain it belongs to is either
suspended or resumed.
* - ``zephyr,pm-device-runtime-auto``
- ``boolean``
- .. code-block:: none
Automatically configure the device for runtime power management after the
init function runs.
Child node properties
=====================
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``reg``
- ``int``
- .. code-block:: none
The PCNT unit index.
The ESP32 has 8 PCNT units. ESP32S2/S3 have 4 PCNT units.
This property is **required**.
Legal values: ``0``, ``1``, ``2``, ``3``, ``4``, ``5``, ``6``, ``7``
See :ref:`dt-important-props` for more information.
* - ``filter``
- ``int``
- .. code-block:: none
Pulse length (ns) to be ignored
Grandchild node properties
==========================
.. list-table::
:widths: 1 1 4
:header-rows: 1
* - Name
- Type
- Details
* - ``reg``
- ``int``
- .. code-block:: none
The PCNT channel index.
This property is **required**.
Legal values: ``0``, ``1``
See :ref:`dt-important-props` for more information.
* - ``sig-pos-mode``
- ``int``
- .. code-block:: none
Define what to do on the positive edge of pulse input.
0 (Default) - Inhibit counter (counter value will not change in this condition).
1 - Increase counter value.
2 - Decrease counter value.
Legal values: ``0``, ``1``, ``2``
* - ``sig-neg-mode``
- ``int``
- .. code-block:: none
Define what to do on the negative edge of pulse input.
0 (Default) - Inhibit counter (counter value will not change in this condition).
1 - Increase counter value.
2 - Decrease counter value.
Legal values: ``0``, ``1``, ``2``
* - ``ctrl-h-mode``
- ``int``
- .. code-block:: none
Define what to do when the control input is high.
0 (Default) - Don't change counter mode.
1 - Invert counter mode(increase -> decrease, decrease -> increase).
2 - Control mode: Inhibit counter (counter value will not change in this condition).
Legal values: ``0``, ``1``, ``2``
* - ``ctrl-l-mode``
- ``int``
- .. code-block:: none
Define what to do when the control input is low.
0 (Default) - Don't change counter mode.
1 - Invert counter mode(increase -> decrease, decrease -> increase).
2 - Control mode: Inhibit counter (counter value will not change in this condition).
Legal values: ``0``, ``1``, ``2``