Problem with Java and Button (GroveDigitalIn)

[mickaelbaron]

Hi the community,

I'm trying to use Java language with GrovePI. My development is based on the Software/Java8 directory.

All sensors from the GrovePi+ Starter kit are working in Java excepted the button sensor. I obtain always the same value even if I press the button.

I know the button sensor is working because I tested it with a Python program.

Here is a snippet which uses GrovePi API (Software/Java8).

public class Button {
    public static void main(String[] args) throws InterruptedException, IOException {
	GrovePi grovePi = new GrovePi4J();
	GroveDigitalIn button = grovePi.getDigitalIn(6);

	while (true) {
	    try {
		System.out.println(button.get());
		Thread.sleep(500);
	    } catch (IOException ex) {
	    }
	}
    }
}

Here is a snippet where I've isolated the problem (pure PI4J).

public class ButtonIssue {

    private static final int dRead_cmd = 1;
    private static final int unused = 0;
    private static final int GROVEPI_ADDRESS = 4;
    private static final byte PIN_MODE_COMMAND = 5;
    private static final byte PIN_MODE_INPUT = 0;
    private static final int PIN = 6;

    private I2CDevice device;
    
    public ButtonIssue() throws IOException, InterruptedException, UnsupportedBusNumberException {
	    I2CBus bus = I2CFactory.getInstance(I2CBus.BUS_1);
	    device = bus.getDevice(GROVEPI_ADDRESS);

	    writeI2c(PIN_MODE_COMMAND, PIN, PIN_MODE_INPUT, unused);

	    while (true) {
	        writeI2c(dRead_cmd, PIN, unused, unused);
	        System.out.println(device.read() & 0xff);
	        Thread.sleep(300);
	    }
    }

    public void writeI2c(int... bytes) throws IOException {
	    // Convert array: int[] to byte[]
	    final ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
	    for (int i = 0; i < bytes.length; i++) {
	        byteBuffer.put((byte) bytes[i]);
	    }
	    device.write(1, byteBuffer.array(), 0, byteBuffer.limit());
    }

    public static void main(String[] args) throws IOException, InterruptedException, UnsupportedBusNumberException {
	    new ButtonIssue();
    }
}

I supposed that writeI2c with read command has a problem. Maybe, someone can test these snippets to confirm this issue?

Thx

[vcutrona]

Hi, quite an old post, but we experienced the same on some new GrovePi boards. Downgrading the GrovePi firmware to v1.2.7 fixes the issue (we tried also v1.3.0, but it is affected by the same bug).

To downgrade the firmware, we just cloned this repo, then copy-pasted the firmware grove_pi_v1_2_7.cpp.hex from Firmware/Archive to Firmware and renamed it grove_pi_firmware.hex, and finally executed ./firmware_update.sh.

[mickaelbaron]

Hi @vcutrona,

I didn't remember about this problem ... thank you for your workaround.

Mickael