From 7005310d612d9c19cccfa3e275ae47277aaeff6a Mon Sep 17 00:00:00 2001
From: DAVe3283 <DAVe3283@gmail.com>
Date: Sun, 24 Aug 2025 17:41:44 -0400
Subject: [PATCH] =?UTF-8?q?Support=20different=20I=C2=B2C=20frequencies=20?=
 =?UTF-8?q?per=20channel?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 content/components/tca9548a.md | 36 +++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/content/components/tca9548a.md b/content/components/tca9548a.md
index 2914639ac9..e59be24dc3 100644
--- a/content/components/tca9548a.md
+++ b/content/components/tca9548a.md
@@ -9,24 +9,34 @@ params:
 
 The TCA9548A component allows you to use TCA9548A as a I²C multiplexer
 ([datasheet](https://www.ti.com/lit/ds/symlink/tca9548a.pdf),
-`AdaFruit`_) in ESPHome. It uses [I²C Bus](#i2c) for communication.
+[Adafruit](https://www.adafruit.com/product/2717)) in ESPHome. It uses [I²C Bus](#i2c) for communication.
+
+{{< img src="tca9548a.jpg" alt="Image" caption="tca9548a I2C Multiplexer." width="80.0%" class="align-center" >}}
 
 Once configured, you can use any of the 8 channels (TCA9548A) as separated channels for your projects.
-Every Channel acts for all connected components as a virtual I²C Bus.
+Each channel acts as a virtual I²C Bus for the connected components, and can be set to a different frequency than the main I²C bus.
 
-{{< img src="tca9548a.jpg" alt="Image" caption="tca9548a I2C Multiplexer." width="80.0%" class="align-center" >}}
+Please note that the main (upstream) I²C bus frequency will be temporarily changed to the frequency of the active channel, so the devices on the main bus must be able to gracefully handle all selected channel speeds!
+This is usually not a problem if the channels are all the same or slower than the main bus.
 
 ```yaml
+# Main I²C bus needs an ID so the multiplexer knows which upstream bus to use
+i2c:
+  id: i2c0
+  scl: SCL
+  sda: SDA
+  frequency: 400 kHz
+
 # Example configuration entry
 tca9548a:
   - address: 0x70
-    id: multiplex0
     i2c_id: i2c0
     channels:
       - bus_id: multiplex0channel0
         channel: 0
       - bus_id: multiplex0channel1
         channel: 1
+        frequency: 100 kHz
 
 # Individual I2C Devices
 sensor:
@@ -36,17 +46,21 @@ sensor:
 
 ## Configuration variables
 
-- **id** (**Required**, [ID](#config-id)): The id to use for this TCA9548A component.
-- **address** (*Optional*, int): The I²C address of the Multiplexer.
+- **id** (*Optional*, [ID](#config-id)): The ID for this TCA9548A component.
+
+- **address** (*Optional*, int): Manually specify the I²C address of the multiplexer.
   Defaults to `0x70`.
 
-- **i2c_id** (*Optional*): The I²C Bus ID
-  Defaults to `false`
+- **i2c_id** (**Required**, [ID](#config-id)): The upstream I²C bus ID to use.
+
+- **channels** (*Optional*): The virtual I²C bus channels
+
+  - **bus_id** (**Required**, [ID](#config-id)): The id to use for this virtual I²C bus.
 
-- **channels** (*Optional*): The I²C Bus Channels
+  - **channel** (**Required**): The channel (0-7) to use for this virtual I²C bus.
 
-  - **bus_id** (**Required**, [ID](#config-id)): The id to use for this virtual I2C Bus.
-  - **channel** (**Required**): The channel (0-7) to use for this virtual I2C Bus.
+  - **frequency** (*Optional*, float): The frequency for this virtual I²C bus.
+    Defaults to `0` (uses the main bus speed).
 
 ### See Also