add freeRTOS port doc

Author: tothero

README.md

@@ -41,6 +41,11 @@ fn main() {
     // The `FreeRTOSConfig.h` is usually inside your main crate to match you application and target needs.
     b.freertos_config("src"); 
 
+    // set the freertos port dir relativ to the FreeRTOS/Source/portable directory
+    // "GCC/ARM_CM33_NTZ/non_secure"
+    // If not set it will be detected based on the current build target (not many targets supported yet)
+    b.freertos_port("GCC/ARM_CM33_NTZ/non_secure");
+
     // Additional "C" code may optionally compiled beside FreeRTOS using:
     // b.get_cc().file("optionalAdditionCode.c");
 

freertos-cargo-build/README.md

@@ -20,12 +20,30 @@ and subdirectories `include` and `portable`. The correct port is automatically d
 
 The `FreeRTOSConfig.h` is usually inside your main crate to match you application and target needs.
 
+Add this snippet to your apps `build.rs`:
 ```
+use std::env;
+
+fn main() {
     let mut b = freertos_cargo_build::Builder::new();
+
+    // Path to copy of the FreeRTOS kernel "C" code
     b.freertos("FreeRTOS/Source");
-    b.freertos_config("src/freertos");
-    b.compile().unwrap_or_else(|e| {panic!(e.to_string())});
-```
+
+    // The `FreeRTOSConfig.h` is usually inside your main crate to match you application and target needs.
+    b.freertos_config("src"); 
+
+    // set the freertos port dir relativ to the FreeRTOS/Source/portable directory
+    // "GCC/ARM_CM33_NTZ/non_secure"
+    // If not set it will be detected based on the current build target (not many targets supported yet)
+    b.freertos_port("GCC/ARM_CM33_NTZ/non_secure");
+
+    // Additional "C" code may optionally compiled beside FreeRTOS using:
+    // b.get_cc().file("optionalAdditionCode.c");
+
+    // Compiles the FreeRTOS "C" Code
+    b.compile().unwrap_or_else(|e| { panic!(e.to_string()) });
+}
 
 ### Select FreeRTOS port
 See: `freertos_cargo_build::Builder::freertos_port(...)`