A problem about serial port on i.MX6Q-SDB

[pengxingwei]

Dear all,

     Hello,My development board is equipped with Android system,I write a serial test apk,this app can set  the serial parameters like baudrate,but when I write or read data from the serial port I set ,

There was an error message:You do not have read/write permission to the serial port. How to solve the problem?Thank you !

[art]

The most likely cause of the issue is that the serial port hardware and corresponding I/O signals have not been properly initialized at the boot-up time. What exactly serial port are you trying to use? Please specify.

Have a great day,
Artur

[pengxingwei]

I've tried many different ways according to some bbs suggestion such as modfying init.rc ,but the problem can't be solved.

[pengxingwei]

the seria port what I used is the ttymxc2.If there are problem about initialization,therefore how to initialize  at the boot-up time for the I/O singals .And the app can find the ttymxc2 and configure it .my system is android 4.3.

[weidong_sun]

Hello Xingwei,

      There are 2 ways to realize what you want , see following , please !

1. Operating Serial port on android application

The way is just like what you are using, but you should change the permission of read/write by console or add command in init.rc

2. Regular operation on android platform

On android platform, from JAVA application to hardware, the loading proceduer is JAVA--->JNI---->C/C++ lib---->hardware, so the better way for your application is to write a operational lib based on C/C++ to operate serial port , then convert the c/c++ lib to JAVA lib through NDK tool, after these jobs are done, your application can load JAVA lib for serial operation.

Hope above suggestions can help you !

If above suggestions can solve your problems, click "correct botton" or "Helpful button" to close the ticket !

Regards,

Weidong

[pengxingwei]

this is the  part of SerialPort.java.

When I operate the app on a button ,

there was an error message:You do not have read/write permission to the serial port.and the eclipse logcat show:

then ,I scan the system file ,find there is no the su file at /system/bin or /system/xbin. for this problem ,how to solve this problem.

[pengxingwei]

Thanks for your reply,my android app of serial has already add the jni,after being compiled ,generated the .so file:libserial_port.so,  so the application has had the c/c++ lib.