Serial multiplexed display

components/display/serial_multiplexed_display.rst

@@ -0,0 +1,79 @@
+Serial Shift Register Multiplexed Displays
+==========================================
+
+.. seo::
+    :description: Instructions for setting up a serial shift register based display.
+    :image: serial_multiplexed_display.jpg
+
+The ``serial_multiplexed_display`` display platform allows you to use (for now) two different kinds of serial shift registers to drive segment displays with ESPHome.
+
+.. figure:: images/serial_multiplexed_display.jpg
+    :align: center
+    :width: 75.0%
+
+    SN74HC595 Serial Shift Register.
+
+These devices normally require three GPIO inputs, clock, data, and latch.  These pins can be configured for the component like below.
+
+
+.. code-block:: yaml
+
+    # Example configuration entry
+    display:
+    - platform: serial_multiplexed_display
+      model: sn74hc595
+      latch_pin: GPIO35
+      clk_pin: GPIO34
+      data_pin: GPIO33
+      common_cathode: True
+      reversed: True
+      lambda: |-
+        it.printf("%s", "1234");
+
+Configuration variables:
+------------------------
+
+- **model** (**Required**, string): The model of the shift register, one of ``sn74hc595``, or ``ct1642``.
+- **data_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin for serial data.
+- **clk_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin for the serial clock.
+- **latch_pin** (**Required**, :ref:`Pin Schema <config-pin_schema>`): The pin for the latch signal.
+- **length** (*Optional*, int): The number of segment displays connected to the shift registers. (defaults to 4, must be between 1 and 8)
+- **lambda** (*Optional*, :ref:`lambda <config-lambda>`): The lambda to use for rendering the content on the TM1621.
+  See :ref:`display-serial_multiplexed_display_lambda` for more information.
+- **common_cathode** (*Optional*, boolean): True if the displays are configured as common cathode.
+- **reversed** (*Optional*, boolean): True to reverse the display order of the segment displays.
+- **update_interval** (*Optional*, :ref:`config-time`): The interval to re-draw the screen. Defaults to ``1s``.
+- **id** (*Optional*, :ref:`config-id`): Manually specify the ID used for code generation.
+
+.. _display-serial_multiplexed_display_lambda:
+
+Rendering Lambda
+----------------
+
+This component has a similar API to the fully fledged :ref:`display-engine`, but it's only a subset as it's intended to
+be used with segment displays (such as 7 segments) and does not have a concept of individual pixels.
+In the lambda you're passed a variable called ``it`` as with all other displays. In this case however, ``it`` is a SerialMultiplexedDisplay
+instance (see API Reference).
+
+The most basic operation is writing a simple number to the screen as in the configuration example
+at the top of this page. But even though you're passing in a string (here ``"1234"``), ESPHome converts it
+into a representation that the connected segments can understand.
+
+This component does not support the decimal point on displays, yet.
+
+.. code-block:: yaml
+
+    display:
+      - platform: serial_multiplexed_display
+        # ...
+      lambda: |-
+        it.printf("%d", id(my_sensor1).state);
+
+
+Please see :ref:`display-printf` for a quick introduction into the ``printf`` formatting rules.
+
+See Also
+--------
+
+- :doc:`index`
+- :ghedit:`Edit`

components/index.rst

@@ -745,6 +745,7 @@ Display Hardware Platforms
     PVVX MiThermometer, components/display/pvvx_mithermometer, xiaomi_lywsd03mmc.jpg
     Quad SPI Displays, components/display/qspi_dbi, t4-s3.jpg
     RPI_DPI_RGB, components/display/rpi_dpi_rgb, waveshare_touch-s3.jpg
+    Serial Multiplexed Displays, components/display/serial_multiplexed_display, serial_multiplexed_display.jpg
     SSD1306, components/display/ssd1306, ssd1306.jpg
     SSD1322, components/display/ssd1322, ssd1322.jpg
     SSD1325, components/display/ssd1325, ssd1325.jpg