platform: add radxa zero3 support

Signed-off-by: Nascs <nascs@radxa.com>

docs/index.java.md

@@ -62,6 +62,7 @@ Specific platform information for supported platforms is documented here:
 - @ref radxa_rock_3c
 - @ref radxa_rock_5a
 - @ref radxa_rock_5b
+- @ref radxa_zero3
 - @ref rockpi4
 
 ## DEBUGGING

docs/index.md

@@ -70,6 +70,7 @@ Specific platform information for supported platforms is documented here:
 - @ref radxa_rock_3c
 - @ref radxa_rock_5a
 - @ref radxa_rock_5b
+- @ref radxa_zero3
 - @ref rockpi4
 
 ## DEBUGGING

docs/radxa_zero3.md

@@ -0,0 +1,20 @@
+Radxa ZERO 3 {#_Radxa}
+=====================
+
+Radxa ZERO 3 is an ultra-small, versatile platform that can be used for a wide variety of applications, including IoT devices, machine learning edge computing, home automation, education, and entertainment.
+
+The ZERO 3W and ZERO 3E differ only in storage and network interfaces. 
+
+Pin Mapping
+-----------
+
+The Radxa ZERO 3's GPIO pinout is compatible with the [Radxa ROCK 3C](./radxa_rock_3c.md).
+
+Supports
+--------
+
+You can find additional product support in the following channels:
+
+- [Product Info](https://docs.radxa.com/en/zero/zero3)
+- [Forums](https://forum.radxa.com/c/rock3)
+- [Github](https://github.com/radxa)