Hi goto-san,
Thank you for answering my problem.
I could check RS232C pin were controlled by my application on the provided Yocto image.
Then, I have two additional question.
Is controlling RS232C the only difference between the provided Yocto image(Customized R13.3) and a Yocto image(Original R13.3) ?
In other words, I think the difference is that a image includes the customized “gpiolib-sysfs.c” or not.
Is the provided URL always accessible?
I am worried about the URL downs and I need a workaround to get it.