Support for building and running external apps (#112)

Libraries/elf_loader/examples/elf_loader_example/README.md

@@ -0,0 +1,50 @@
+## ELF Loader Example
+
+This example shows how to use ELF loader to run ELF file.
+
+## How to Use Example
+
+Before project configuration and build, be sure to set the correct chip target using `idf.py set-target <chip_name>`.
+
+* Note: Only ESP32, ESP32-S2 and ESP32-S3 are supported
+
+### Hardware Required
+
+* A development board based on espressif ESP32/ESP32-S2/ESP32-S3 SoC
+* A USB cable for power supply and programming
+
+### Configure the Project
+
+Open the project configuration menu (`idf.py menuconfig`).
+
+In the `Example Configuration` menu:
+
+* Enable ELF input arguments in the `Support arguments for ELF main` option if necessary.
+* Set the arguments in the `Arguments of ELF main` option.
+
+### Build and Flash
+
+Run `idf.py -p PORT flash monitor` to build, flash and monitor the project.
+
+(To exit the serial monitor, type ``Ctrl-]``.)
+
+## Example Output
+
+As you run the example, you will see the following log:
+
+```
+I (0) cpu_start: Starting scheduler on APP CPU.
+I (382) elf_loader: Start to relocate ELF
+I (392) elf_loader: Start to run ELF
+hello world 0
+hello world 1
+hello world 2
+hello world 3
+hello world 4
+hello world 5
+hello world 6
+hello world 7
+hello world 8
+hello world 9
+I (10392) elf_loader: Success to exit from APP of ELF
+```