CMF Buds 2a: Add equalizer and ultra bass

2026-07-31 07:44:24 +02:00 · 2026-05-03 16:44:35 +01:00
parent 72dcc1db2c
commit c40d3e63a8
11 changed files with 380 additions and 2 deletions
@@ -374,6 +374,9 @@ public class DeviceSettingsPreferenceConst {

    public static final String PREF_NOTHING_EAR1_INEAR = "pref_nothing_inear_detection";
    public static final String PREF_NOTHING_EAR1_AUDIOMODE = "pref_nothing_audiomode";
+    public static final String PREF_NOTHING_EAR1_ULTRA_BASS_ENABLED = "pref_nothing_ultra_bass_enabled";
+    public static final String PREF_NOTHING_EAR1_ULTRA_BASS_LEVEL = "pref_nothing_ultra_bass_level";
+    public static final String PREF_HEADPHONES_EQUALIZER = "pref_headphones_equalizer";
    public static final String PREF_HEADPHONES_LOW_LATENCY = "pref_headphones_low_latency";


@@ -18,6 +18,9 @@ package nodomain.freeyourgadget.gadgetbridge.devices.nothing;

 import androidx.annotation.NonNull;

+import java.util.Collections;
+import java.util.List;
+
 import nodomain.freeyourgadget.gadgetbridge.R;
 import nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSpecificSettings;
 import nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSpecificSettingsCustomizer;
@@ -66,6 +69,12 @@ public abstract class AbstractEarCoordinator extends AbstractBLClassicDeviceCoor
    public DeviceSpecificSettings getDeviceSpecificSettings(final GBDevice device) {
        final DeviceSpecificSettings deviceSpecificSettings = new DeviceSpecificSettings();
        deviceSpecificSettings.addRootScreen(R.xml.devicesettings_nothing_ear1);
+        if (!getEqualizerPresets().isEmpty()) {
+            deviceSpecificSettings.addRootScreen(R.xml.devicesettings_nothing_equalizer);
+        }
+        if (supportsUltraBass()) {
+            deviceSpecificSettings.addRootScreen(R.xml.devicesettings_nothing_ultra_bass);
+        }
        if (supportsLowLatency()) {
            deviceSpecificSettings.addRootScreen(R.xml.devicesettings_headphones_low_latency);
        }
@@ -100,4 +109,12 @@ public abstract class AbstractEarCoordinator extends AbstractBLClassicDeviceCoor
    public boolean supportsLowLatency() {
        return false;
    }
+
+    public List<NothingEqualizer> getEqualizerPresets() {
+        return Collections.emptyList();
+    }
+
+    public boolean supportsUltraBass() {
+        return false;
+    }
 }
@@ -16,6 +16,9 @@
    along with this program.  If not, see <https://www.gnu.org/licenses/>. */
 package nodomain.freeyourgadget.gadgetbridge.devices.nothing;

+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
 import java.util.regex.Pattern;

 import nodomain.freeyourgadget.gadgetbridge.R;
@@ -70,4 +73,21 @@ public class CmfBuds2aCoordinator extends AbstractEarCoordinator {
    public boolean supportsLowLatency() {
        return true;
    }
+
+    @Override
+    public List<NothingEqualizer> getEqualizerPresets() {
+        return Arrays.asList(
+                NothingEqualizer.POP,
+                NothingEqualizer.ROCK,
+                NothingEqualizer.ELECTRONIC,
+                NothingEqualizer.ENHANCE_VOCALS,
+                NothingEqualizer.CLASSICAL,
+                NothingEqualizer.DIRAC
+        );
+    }
+
+    @Override
+    public boolean supportsUltraBass() {
+        return true;
+    }
 }
@@ -18,6 +18,7 @@ package nodomain.freeyourgadget.gadgetbridge.devices.nothing;

 import android.os.Parcel;

+import androidx.annotation.NonNull;
 import androidx.preference.ListPreference;
 import androidx.preference.Preference;

@@ -32,7 +33,7 @@ import nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSpec
 import nodomain.freeyourgadget.gadgetbridge.util.Prefs;

 public class EarSettingsCustomizer implements DeviceSpecificSettingsCustomizer {
-    public static final Creator<EarSettingsCustomizer> CREATOR = new Creator<EarSettingsCustomizer>() {
+    public static final Creator<EarSettingsCustomizer> CREATOR = new Creator<>() {
        @Override
        public EarSettingsCustomizer createFromParcel(final Parcel in) {
            return new EarSettingsCustomizer();
@@ -88,6 +89,33 @@ public class EarSettingsCustomizer implements DeviceSpecificSettingsCustomizer {
            ((ListPreference) audioModePref).setEntries(entries.toArray(new CharSequence[0]));
            ((ListPreference) audioModePref).setEntryValues(entryValues.toArray(new CharSequence[0]));
        }
+
+        final Preference equalizerPref = handler.findPreference(DeviceSettingsPreferenceConst.PREF_HEADPHONES_EQUALIZER);
+        if (equalizerPref instanceof ListPreference listPreference) {
+            final List<NothingEqualizer> supportedPresets = earCoordinator.getEqualizerPresets();
+            if (supportedPresets.isEmpty()) {
+                listPreference.setVisible(false);
+            } else {
+                final CharSequence[] originalEntries = listPreference.getEntries();
+                final CharSequence[] originalEntryValues = listPreference.getEntryValues();
+
+                final List<CharSequence> entries = new ArrayList<>();
+                final List<CharSequence> entryValues = new ArrayList<>();
+
+                for (int i = 0; i < originalEntryValues.length; i++) {
+                    final NothingEqualizer preset = NothingEqualizer.fromPreferenceValue(originalEntryValues[i].toString());
+                    if (preset == null || !supportedPresets.contains(preset)) {
+                        continue;
+                    }
+
+                    entries.add(originalEntries[i]);
+                    entryValues.add(originalEntryValues[i]);
+                }
+
+                listPreference.setEntries(entries.toArray(new CharSequence[0]));
+                listPreference.setEntryValues(entryValues.toArray(new CharSequence[0]));
+            }
+        }
    }

    @Override
@@ -101,6 +129,6 @@ public class EarSettingsCustomizer implements DeviceSpecificSettingsCustomizer {
    }

    @Override
-    public void writeToParcel(final Parcel dest, final int flags) {
+    public void writeToParcel(@NonNull final Parcel dest, final int flags) {
    }
 }
@@ -0,0 +1,43 @@
+package nodomain.freeyourgadget.gadgetbridge.devices.nothing;
+
+public enum NothingEqualizer {
+    ROCK((byte) 0x01),
+    ELECTRONIC((byte) 0x02),
+    POP((byte) 0x03),
+    ENHANCE_VOCALS((byte) 0x04),
+    CLASSICAL((byte) 0x05),
+    DIRAC((byte) 0x07),
+    ;
+
+    private final byte code;
+
+    NothingEqualizer(final byte code) {
+        this.code = code;
+    }
+
+    public byte getCode() {
+        return this.code;
+    }
+
+    public static NothingEqualizer fromCode(final byte code) {
+        for (NothingEqualizer value : NothingEqualizer.values()) {
+            if (value.getCode() == code) {
+                return value;
+            }
+        }
+
+        return null;
+    }
+
+    public static NothingEqualizer fromPreferenceValue(final String preferenceValue) {
+        if (preferenceValue == null) {
+            return null;
+        }
+
+        try {
+            return NothingEqualizer.valueOf(preferenceValue);
+        } catch (final IllegalArgumentException e) {
+            return null;
+        }
+    }
+}
@@ -37,6 +37,7 @@ import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEventUpdateDevi
 import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEventUpdatePreferences;
 import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEventVersionInfo;
 import nodomain.freeyourgadget.gadgetbridge.devices.nothing.AbstractEarCoordinator;
+import nodomain.freeyourgadget.gadgetbridge.devices.nothing.NothingEqualizer;
 import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
 import nodomain.freeyourgadget.gadgetbridge.model.BatteryState;
 import nodomain.freeyourgadget.gadgetbridge.service.AbstractHeadphoneBTBRDeviceSupport;
@@ -74,6 +75,12 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
        sendCommand(builder, nothingProtocol.encodeFirmwareVersionReq());
        sendCommand(builder, nothingProtocol.encodeBatteryStatusReq());
        sendCommand(builder, nothingProtocol.encodeAudioModeStatusReq());
+        if (!getCoordinator().getEqualizerPresets().isEmpty()) {
+            sendCommand(builder, nothingProtocol.encodeEqualizerStatusReq());
+        }
+        if (getCoordinator().supportsUltraBass()) {
+            sendCommand(builder, nothingProtocol.encodeUltraBassStatusReq());
+        }

        return builder;
    }
@@ -135,6 +142,19 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
                // OFF:          55 6001 40F0 0100 5C 02 28 9353
                // OFF Response: 55 6001 4070 0000 5C FF FF95
                break;
+            case DeviceSettingsPreferenceConst.PREF_HEADPHONES_EQUALIZER:
+                sendCommand("set equalizer", nothingProtocol.encodeEqualizer(prefs.getString(DeviceSettingsPreferenceConst.PREF_HEADPHONES_EQUALIZER, NothingEqualizer.DIRAC.name())));
+                break;
+            case DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_ENABLED:
+            case DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_LEVEL:
+                sendCommand(
+                        "set ultra bass",
+                        nothingProtocol.encodeUltraBass(
+                                prefs.getBoolean(DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_ENABLED, false),
+                                prefs.getInt(DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_LEVEL, 2)
+                        )
+                );
+                break;
            default:
                LOG.debug("CONFIG: " + config);
                break;
@@ -166,6 +186,8 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
        private static final short audio_mode_status = (short) 0xc01e;
        private static final short audio_mode_status2 = (short) 0xe003;
        private static final short low_latency = (short) 0xf040;
+        private static final short equalizer_status = (short) 0xc050;
+        private static final short ultra_bass_status = (short) 0xc04e;

        private static final short unk_maybe_ack = (short) 0xf002;
        private static final short unk_close_case = (short) 0xe002; //sent twice when the case is closed with earphones in
@@ -175,6 +197,8 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
        private static final short in_ear_detection = (short) 0xf004;
        private static final short in_ear_detection2 = (short) 0xc00e;
        private static final short audio_mode = (short) 0xf00f;
+        private static final short equalizer = (short) 0xf01d;
+        private static final short ultra_bass = (short) 0xf051;

        private final boolean incrementCounter;
        private int messageCounter = 0x00;
@@ -259,6 +283,20 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
                    devEvts.add(handleInEarStatus(payload));
                    break;

+                case equalizer_status:
+                case equalizer:
+                    if (payload.length > 0) {
+                        devEvts.add(handleEqualizerStatus(payload));
+                    }
+                    break;
+
+                case ultra_bass_status:
+                case ultra_bass:
+                    if (payload.length > 0) {
+                        devEvts.add(handleUltraBassStatus(payload));
+                    }
+                    break;
+
                case unk_maybe_ack:
                    LOG.debug("received ack");
                    break;
@@ -320,6 +358,14 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
            return encodeMessage((short) 0x120, audio_mode_status, new byte[]{});
        }

+        byte[] encodeEqualizerStatusReq() {
+            return encodeMessage((short) 0x120, equalizer_status, new byte[]{});
+        }
+
+        byte[] encodeUltraBassStatusReq() {
+            return encodeMessage((short) 0x120, ultra_bass_status, new byte[]{});
+        }
+
        private GBDeviceEventVersionInfo handleFirmwareVersion(byte[] payload) {
            GBDeviceEventVersionInfo evt = new GBDeviceEventVersionInfo();
            evt.fwVersion = new String(payload);
@@ -351,6 +397,32 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
            return preferencesEvent;
        }

+        private GBDeviceEventUpdatePreferences handleEqualizerStatus(final byte[] payload) {
+            final GBDeviceEventUpdatePreferences preferencesEvent = new GBDeviceEventUpdatePreferences();
+
+            final NothingEqualizer equalizerPreset = NothingEqualizer.fromCode(payload[0]);
+            if (equalizerPreset == null) {
+                LOG.warn("Unknown equalizer code: {}", payload[0] & 0xff);
+                return preferencesEvent;
+            }
+
+            preferencesEvent.withPreference(DeviceSettingsPreferenceConst.PREF_HEADPHONES_EQUALIZER, equalizerPreset.name());
+            return preferencesEvent;
+        }
+
+        private GBDeviceEventUpdatePreferences handleUltraBassStatus(final byte[] payload) {
+            final GBDeviceEventUpdatePreferences preferencesEvent = new GBDeviceEventUpdatePreferences();
+
+            preferencesEvent.withPreference(DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_ENABLED, payload[0] == 0x01);
+
+            if (payload.length >= 2) {
+                final int level = Math.max(1, Math.min(5, ((payload[1] & 0xff) + 1) / 2));
+                preferencesEvent.withPreference(DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_LEVEL, level);
+            }
+
+            return preferencesEvent;
+        }
+
        byte[] encodeInEarDetection(byte enabled) {
            return encodeMessage((short) 0x120, in_ear_detection, new byte[]{0x01, 0x01, enabled});
        }
@@ -372,6 +444,26 @@ public class Ear1Support extends AbstractHeadphoneBTBRDeviceSupport {
            return encodeMessage((short) 0x120, low_latency, new byte[]{payload});
        }

+        byte[] encodeEqualizer(final String desired) {
+            NothingEqualizer preset = NothingEqualizer.DIRAC;
+
+            final NothingEqualizer requested = NothingEqualizer.fromPreferenceValue(desired);
+            if (requested != null) {
+                preset = requested;
+            } else {
+                LOG.warn("Unknown equalizer preset: {}, using default", desired);
+            }
+
+            return encodeMessage((short) 0x120, equalizer, new byte[]{preset.getCode(), 0x00});
+        }
+
+        byte[] encodeUltraBass(final boolean enabled, final int level) {
+            final int clampedLevel = Math.max(1, Math.min(5, level));
+            final byte rawLevel = (byte) (clampedLevel * 2);
+
+            return encodeMessage((short) 0x120, ultra_bass, new byte[]{(byte) (enabled ? 0x01 : 0x00), rawLevel});
+        }
+
        public byte[] encodeFindDevice(boolean start) {
            byte payload = (byte) (start ? 0x01 : 0x00);
            return encodeMessage((short) 0x120, find_device, new byte[]{payload});
@@ -3564,6 +3564,24 @@
        <item>off</item>
    </string-array>

+    <string-array name="nothing_ear1_equalizer_names">
+        <item>@string/nothing_equalizer_rock</item>
+        <item>@string/nothing_equalizer_electronic</item>
+        <item>@string/nothing_equalizer_pop</item>
+        <item>@string/nothing_equalizer_enhance_vocals</item>
+        <item>@string/nothing_equalizer_classical</item>
+        <item>@string/nothing_equalizer_dirac</item>
+    </string-array>
+
+    <string-array name="nothing_ear1_equalizer_values">
+        <item>ROCK</item>
+        <item>ELECTRONIC</item>
+        <item>POP</item>
+        <item>ENHANCE_VOCALS</item>
+        <item>CLASSICAL</item>
+        <item>DIRAC</item>
+    </string-array>
+
    <string-array name="notification_list_is_blacklist_names">
        <item>@string/pref_title_notification_use_as_deny</item>
        <item>@string/pref_title_notification_use_as_allow</item>
@@ -3177,6 +3177,15 @@
    <string name="nothing_prefs_inear_title">In-Ear detection</string>
    <string name="prefs_in_ear_detection_summary">Play calls through your earbuds when they are in your ears</string>
    <string name="nothing_prefs_audiomode_title">Audio mode</string>
+    <string name="nothing_prefs_ultra_bass_title">Ultra Bass</string>
+    <string name="nothing_prefs_ultra_bass_summary">Boost low frequencies for a stronger bass response</string>
+    <string name="nothing_prefs_ultra_bass_level_title">Ultra Bass Level</string>
+    <string name="nothing_equalizer_rock">Rock</string>
+    <string name="nothing_equalizer_electronic">Electronic</string>
+    <string name="nothing_equalizer_pop">Pop</string>
+    <string name="nothing_equalizer_enhance_vocals">Enhance vocals</string>
+    <string name="nothing_equalizer_classical">Classical</string>
+    <string name="nothing_equalizer_dirac">Dirac</string>
    <string name="prefs_equalizer_preset">Equalizer Preset</string>
    <string name="pref_title_equalizer_normal">Normal</string>
    <string name="pref_title_equalizer_bass_boost">Bass boost</string>
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <ListPreference
+        android:icon="@drawable/ic_equalizer"
+        android:entryValues="@array/nothing_ear1_equalizer_values"
+        android:entries="@array/nothing_ear1_equalizer_names"
+        android:key="pref_headphones_equalizer"
+        app:useSimpleSummaryProvider="true"
+        android:title="@string/prefs_equalizer_preset" />
+</androidx.preference.PreferenceScreen>
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <SwitchPreferenceCompat
+        android:defaultValue="false"
+        android:icon="@drawable/ic_speaker"
+        android:key="pref_nothing_ultra_bass"
+        android:layout="@layout/preference_checkbox"
+        android:summary="@string/nothing_prefs_ultra_bass_summary"
+        android:title="@string/nothing_prefs_ultra_bass_title" />
+    <SeekBarPreference
+        android:defaultValue="2"
+        android:dependency="pref_nothing_ultra_bass"
+        android:icon="@drawable/ic_speaker"
+        android:key="pref_nothing_ultra_bass_level"
+        android:max="5"
+        android:title="@string/nothing_prefs_ultra_bass_level_title"
+        app:min="1"
+        app:showSeekBarValue="true" />
+</androidx.preference.PreferenceScreen>
@@ -0,0 +1,117 @@
+package nodomain.freeyourgadget.gadgetbridge.service.devices.nothing;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSettingsPreferenceConst;
+import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEvent;
+import nodomain.freeyourgadget.gadgetbridge.deviceevents.GBDeviceEventUpdatePreferences;
+import nodomain.freeyourgadget.gadgetbridge.devices.nothing.NothingEqualizer;
+import nodomain.freeyourgadget.gadgetbridge.test.TestBase;
+import nodomain.freeyourgadget.gadgetbridge.util.GB;
+
+import static nodomain.freeyourgadget.gadgetbridge.util.CheckSums.getCRC16ansi;
+
+public class NothingProtocolTest extends TestBase {
+    @Test
+    public void testDecodeEqualizerAndUltraBassStatus() {
+        final Ear1Support.NothingProtocol protocol = new Ear1Support.NothingProtocol(true);
+
+        final GBDeviceEvent[] equalizerEvents = protocol.decodeResponse(GB.hexStringToByteArray("5560015040010060057f43"));
+        final GBDeviceEventUpdatePreferences equalizerUpdate = findEvent(equalizerEvents, GBDeviceEventUpdatePreferences.class);
+        Assert.assertNotNull(equalizerUpdate);
+        Assert.assertEquals(NothingEqualizer.CLASSICAL.name(), equalizerUpdate.preferences.get(DeviceSettingsPreferenceConst.PREF_HEADPHONES_EQUALIZER));
+
+        final GBDeviceEvent[] ultraBassEvents = protocol.decodeResponse(GB.hexStringToByteArray("5560014e4002001b00028071"));
+        final GBDeviceEventUpdatePreferences ultraBassUpdate = findEvent(ultraBassEvents, GBDeviceEventUpdatePreferences.class);
+        Assert.assertNotNull(ultraBassUpdate);
+        Assert.assertEquals(false, ultraBassUpdate.preferences.get(DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_ENABLED));
+        Assert.assertEquals(1, ultraBassUpdate.preferences.get(DeviceSettingsPreferenceConst.PREF_NOTHING_EAR1_ULTRA_BASS_LEVEL));
+    }
+
+    @Test
+    public void testEncodeEqualizerCommand() {
+        final Ear1Support.NothingProtocol protocol = new Ear1Support.NothingProtocol(true);
+
+        final byte[] packet = protocol.encodeEqualizer(NothingEqualizer.ELECTRONIC.name());
+        final byte[] expected = GB.hexStringToByteArray("5560011df00200140200ebcd");
+        assertMessageEquals(expected, packet);
+    }
+
+    @Test
+    public void testEncodeUltraBassCommand() {
+        final Ear1Support.NothingProtocol protocol = new Ear1Support.NothingProtocol(true);
+
+        final byte[] packet = protocol.encodeUltraBass(true, 2);
+        final byte[] expected = GB.hexStringToByteArray("55600151f0020070010426e5");
+        assertMessageEquals(expected, packet);
+    }
+
+    private void assertMessageEquals(final byte[] expected, final byte[] actual) {
+        Assert.assertNotNull(expected);
+        Assert.assertNotNull(actual);
+
+        Assert.assertTrue("message too short", expected.length >= 8 && actual.length >= 8);
+        Assert.assertEquals("sof differs", expected[0], actual[0]);
+
+        final int expectedControl = readLeShort(expected, 1);
+        final int actualControl = readLeShort(actual, 1);
+        Assert.assertEquals("control differs", expectedControl, actualControl);
+
+        final int expectedCommand = readLeShort(expected, 3);
+        final int actualCommand = readLeShort(actual, 3);
+        Assert.assertEquals("command differs", expectedCommand, actualCommand);
+
+        final int expectedPayloadLength = readLeShort(expected, 5);
+        final int actualPayloadLength = readLeShort(actual, 5);
+        Assert.assertEquals("payload length field differs", expectedPayloadLength, actualPayloadLength);
+
+        final boolean expectedCrc = (expectedControl & 0x20) != 0;
+        final boolean actualCrc = (actualControl & 0x20) != 0;
+        Assert.assertEquals("crc flag differs", expectedCrc, actualCrc);
+
+        final int expectedTotalLength = 8 + expectedPayloadLength + (expectedCrc ? 2 : 0);
+        final int actualTotalLength = 8 + actualPayloadLength + (actualCrc ? 2 : 0);
+        Assert.assertEquals("expected message has invalid size", expectedTotalLength, expected.length);
+        Assert.assertEquals("actual message has invalid size", actualTotalLength, actual.length);
+
+        // Counter byte at offset 7 is intentionally ignored.
+        Assert.assertArrayEquals(
+                "payload differs",
+                Arrays.copyOfRange(expected, 8, 8 + expectedPayloadLength),
+                Arrays.copyOfRange(actual, 8, 8 + actualPayloadLength)
+        );
+
+        assertCrcIsValid(expected, expectedCrc);
+        assertCrcIsValid(actual, actualCrc);
+    }
+
+    private static int readLeShort(final byte[] msg, final int offset) {
+        return (msg[offset] & 0xff) | ((msg[offset + 1] & 0xff) << 8);
+    }
+
+    private static void assertCrcIsValid(final byte[] msg, final boolean hasCrc) {
+        if (!hasCrc) {
+            return;
+        }
+
+        final int payloadLength = readLeShort(msg, 5);
+        final int crcOffset = 8 + payloadLength;
+        final int expectedCrc = readLeShort(msg, crcOffset);
+        final int actualCrc = getCRC16ansi(Arrays.copyOf(msg, crcOffset));
+        Assert.assertEquals("invalid crc", expectedCrc, actualCrc);
+    }
+
+    @SuppressWarnings("unchecked")
+    private static <T extends GBDeviceEvent> T findEvent(final GBDeviceEvent[] events, final Class<T> cls) {
+        for (GBDeviceEvent event : events) {
+            if (cls.isInstance(event)) {
+                return (T) event;
+            }
+        }
+
+        return null;
+    }
+}