using serial port RS-232 in android?

Question

I want to send signals via serial port using the JavaComm API classes on an Android device, and here is how I imagine it:

1- the Android device would be: Archos 3.2 which has android 2.2 and USB host mode.

2- include RxTx lib package with my Android app. and include RxTx native code using Android NDK.

3- a short cable which is usb-->serial.

Could you explain to me where I might face problems?

Answer 1

I just ported the JavaCOMM ( GNU RXTX ) library to the Android. Here is the link http://v-lad.org/projects/gnu.io.android/

You still might need to rebuild your kernel and maybe recompile the shared library for your environment. But this should get you started.

Answer 2

As noted above, you'll need to come up with device drivers for whatever USB<->Serial device you have. Many of these devices use the Prolific PL2303 chip:

http://www.qbik.ch/usb/devices/showdr.php?id=175

which the stock linux kernel has support for, and has had for a long time. I've used this and it works fine, so I would recommend you stick with USB<->Serial devices that use this chip.

Beyond that, with udev these devices normally show up as /dev/ttyUSB#. How that happens with Android, I don't know, so you'll need to figure that out.

Finally, you will need to build the RxTx native code. This code is pretty crufty - I had problems building it on a fairly modern Angstrom, and I was not trying to cross-compile at all.