ZZ-Cat · ZZ-Cat · Jul 24, 2023 · Jul 16, 2023 · Jul 16, 2023 · Jul 16, 2023
diff --git a/README.md b/README.md
@@ -208,6 +208,7 @@ While CRSF for Arduino is primarily developed on the Adafruit Metro M4 Express,
     - MKR Zero
   - Arduino Nano 33 IoT
   - Arduino Zero
+  - Seeed Studio XIAO SAMD21
 - SAMD51 based boards:
   - Adafruit Feather M4 Express
   - Adafruit Grand Central M4
@@ -251,6 +252,7 @@ Here are some examples:
 - These have an equivalent "breadboard-friendly" form factor that is similar to the Arduio Micro & the Arduino Nano:
   - Adafruit Feather M0 (all variants, including the Feather M0 Express)
   - Adafruit Feather M4 Express
+  - Seeed Studio XIAO SAMD21
 - These have the "Arduino R3" form factor - The same shape as the Arduino UNO:
   - Adafruit:
     - Metro M0 Express
@@ -276,6 +278,10 @@ For wiring, here is how you do it:
 - T (or Tx) on your receiver goes to ►Rx/Pin0 on your development board. This step can catch you out, if you're not careful.
 - R (or Rx) on your reciever goes to ◄Tx/Pin1 on your development board. This step can catch you out, if you're not careful.
 
+**NB:** Some development boards (especially smaller ones) may not route the primary UART port to the default 0 & 1 pins, as these pins may be used for other purposes or they simply are not physically available to you on the device.
+As a workaround, CRSF for Arduino automatically selects the closest available pins that has a suitable UART port.
+You _must_ refer to your development board's documentation to determine where your default Tx & Rx pins are. These are the pins that CRSF for Arduino will use.
+
 ## Telemetry
 
 Currently, there is no telemetry feedback from the host microcontroller's side... _yet!_

diff --git a/examples/channels/channels.ino b/examples/channels/channels.ino
@@ -2,8 +2,8 @@
  * @file channels.ino
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief This example sketch shows how to receive RC channels from a CRSF receiver using the CRSF for Arduino library.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *

diff --git a/library.properties b/library.properties
@@ -1,5 +1,5 @@
 name=CRSFforArduino
-version=0.3.2
+version=0.4.0
 author=Cassandra Robinson <[email protected]>
 maintainer=Cassandra Robinson <[email protected]>
 sentence=An Arduino Library for communicating with ExpressLRS receivers.

diff --git a/platformio.ini b/platformio.ini
@@ -91,6 +91,10 @@ lib_deps = ${common.lib_deps}
 board = mkrzero
 lib_deps = ${common.lib_deps}
 
+[env:seeed_xiao]
+board = seeed_xiao
+lib_deps = ${common.lib_deps}
+
 [env:zero]
 board = zero
 lib_deps = ${common.lib_deps}

diff --git a/src/CRSFforArduino.h b/src/CRSFforArduino.h
@@ -2,8 +2,8 @@
  * @file CRSFforArduino.h
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief Top level header for CRSF for Arduino, to help with Arduino IDE compatibility.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *

diff --git a/src/lib/CRSFforArduino/CRSFforArduino.cpp b/src/lib/CRSFforArduino/CRSFforArduino.cpp
@@ -2,8 +2,8 @@
  * @file CRSFforArduino.cpp
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief CRSF for Arduino facilitates the use of ExpressLRS RC receivers in Arduino projects.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *
@@ -352,6 +352,10 @@ Sercom *CRSFforArduino::_getSercom()
     defined(ARDUINO_SAMD_NANO_33_IOT)
     sercom = SERCOM5;
 
+/* Seeed XIAO. */
+#elif defined(SEEED_XIAO_M0)
+    sercom = SERCOM4;
+
 /* Arduino Zero. */
 #elif defined(ARDUINO_SAMD_ZERO)
     sercom = SERCOM0;

diff --git a/src/lib/CRSFforArduino/CRSFforArduino.h b/src/lib/CRSFforArduino/CRSFforArduino.h
@@ -2,8 +2,8 @@
  * @file CRSFforArduino.h
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief CRSF for Arduino facilitates the use of ExpressLRS RC receivers in Arduino projects.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *

diff --git a/src/lib/CompatibilityTable/CompatibilityTable.cpp b/src/lib/CompatibilityTable/CompatibilityTable.cpp
@@ -2,8 +2,8 @@
  * @file CompatibilityTable.cpp
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief Compatibility Table is used to determine if the current device is compatible with CRSF for Arduino.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *
@@ -73,6 +73,8 @@ CompatibilityTable::CompatibilityTable()
     device.type.devboard = DEVBOARD_ARDUINO_MKRZERO;
 #elif defined(ARDUINO_SAMD_NANO_33_IOT)
     device.type.devboard = DEVBOARD_ARDUINO_NANO_33_IOT;
+#elif defined(SEEED_XIAO_M0)
+    device.type.devboard = DEVBOARD_SEEEDSTUDIO_XIAO_M0;
 #elif defined(ARDUINO_SAMD_ZERO)
     device.type.devboard = DEVBOARD_ARDUINO_ZERO;
 #else

diff --git a/src/lib/CompatibilityTable/CompatibilityTable.h b/src/lib/CompatibilityTable/CompatibilityTable.h
@@ -2,8 +2,8 @@
  * @file CompatibilityTable.h
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief Compatibility Table is used to determine if the current device is compatible with CRSF for Arduino.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *
@@ -73,6 +73,9 @@ class CompatibilityTable
         DEVBOARD_ARDUINO_NANO_33_IOT,
         DEVBOARD_ARDUINO_ZERO,
 
+        // Seeed Studio SAMD21 boards.
+        DEVBOARD_SEEEDSTUDIO_XIAO_M0,
+
         DEVBOARD_COUNT
     } __ct_devboards_t;
 
@@ -112,7 +115,8 @@ class CompatibilityTable
         "Arduino MKRWIFI1010",
         "Arduino MKRZERO",
         "Arduino Nano 33 IoT",
-        "Arduino Zero"};
+        "Arduino Zero",
+        "Seeed Studio Xiao M0"};
 };
 
 // CompatibilityTable CT = CompatibilityTable();
diff --git a/src/library.json b/src/library.json
@@ -1,7 +1,7 @@
 {
     "$schema": "https://raw.githubusercontent.com/platformio/platformio-core/develop/platformio/assets/schema/library.json",
     "name": "CRSFforArduino",
-    "version": "0.3.2",
+    "version": "0.4.0",
     "description": "Arduino library for Crossfire protocol",
     "keywords": [
         "adafruit",

diff --git a/src/src/main_rc.cpp b/src/src/main_rc.cpp
@@ -2,8 +2,8 @@
  * @file main_rc.cpp
  * @author Cassandra "ZZ Cat" Robinson ([email protected])
  * @brief This file demonstrates the full capabilities of CRSF for Arduino.
- * @version 0.3.2
- * @date 2023-06-03
+ * @version 0.4.0
+ * @date 2023-07-17
  *
  * @copyright Copyright (c) 2023, Cassandra "ZZ Cat" Robinson. All rights reserved.
  *