ELFloader and shell command 'exec' example for Sky platform
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Compiles the Contiki hello-world application as a Contiki executable (.ce).
The Contiki executable is then uploaded to the Sky platform via serial, and
is stored in the filesystem.
Finally, the executable is loaded via the shell command 'exec'.
 
NOTE:
You may have to reduce the ELF loader memory usage (/platform/sky/contiki-conf.h).
Since hello-world uses very little memory:
#define ELFLOADER_CONF_DATAMEMORY_SIZE 0x100
#define ELFLOADER_CONF_TEXTMEMORY_SIZE 0x100


1. Upload Sky shell with 'exec' command and symbols (requires several recompilations to generate correct symbols):
> make sky-shell-exec.sky
> make sky-shell-exec.sky CORE=sky-shell-exec.sky
> make sky-shell-exec.upload CORE=sky-shell-exec.sky


2. Verify access to the shell and the filesystem:
> make login
SHELL> echo hello shell
SHELL> echo test | write mytest.txt
SHELL> ls
SHELL> read mytest.txt
[CTRL-C] to exit the shell


3. Upload Contiki executable hello-world.ce:
> make upload-executable
[CTRL-C] to exit the shell when the entire file has been uploaded (after ~30 sec)


4. Verify that hello-world.ce exists in CFS:
> make login
SHELL> ls
SHELL> read hello-world.ce | size
The last command output should equal the size of hello-world.ce in this directory!


5. Load and start hello world:
SHELL> exec hello-world.ce
The program should now start: the output 'Hello, World' appears.

