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Getting an Lidar product (using Lidar Lite v3) to interface with a Raspberry Pi 3 running Android things (using the 0.6.1 preview). At the moment; I'm just trying to scan the I2C1 bus for the active device (looking at 0x62). I have a very simple Android things project but I'm getting a permissions issue. I can't see anything in the documentation about specific permissions needed.

This line in my code:

    for (int address = 0x60; address < 0x70; address++) {
        //auto-close the devices
        try (final I2cDevice device = service.openI2cDevice("I2C1", address)) {

fails with the following exception:

com.google.android.things.pio.PioException: android.os.ServiceSpecificException: Caller does not own I2C1(0x60) (code 13)

Am I missing something?

  • Is this running in the main UI thread? Do you have any other apps installed which may concurrently claim I2C? – Nick Felker Dec 18 '17 at 7:12
  • Nick, This is a "clean" RasPi with fresh Android Things installed. I didn't install anything using I2C; but unsure if the kernel has. Full Source is on GitHub at: github.com/Zitt/RGB_Walkway – John Zitterkopf Dec 19 '17 at 9:13
  • Can you not do the try with resources and just do a regular try? It may be that this format is handling the I/O in an unusual way outside of the normal application context. – Nick Felker Dec 19 '17 at 18:48
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My issue was a misunderstanding of "try-with-resources" which automatically closes the device when the scope is exited. My in scope device.close() was closing and then the "try-with-resources" scope tried to close it a second time which was generating the error.

https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html is a bit dense but has all the information you should need about the try-with-resources block.

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