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Merge pull request #188 from kai-morich/ch340-async

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enable async read for CH340 as in CDC driver to prevent data loss at high baud rates
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kai-morich 2019-10-04 16:49:50 +02:00 committed by GitHub
commit d7147201de
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1 changed files with 36 additions and 0 deletions
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36
usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Ch34xSerialDriver.java
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@ -25,9 +25,12 @@ import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection; import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbEndpoint; import android.hardware.usb.UsbEndpoint;
import android.hardware.usb.UsbInterface; import android.hardware.usb.UsbInterface;
import android.hardware.usb.UsbRequest;
import android.os.Build;
import android.util.Log; import android.util.Log;
import java.io.IOException; import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Collections; import java.util.Collections;
import java.util.LinkedHashMap; import java.util.LinkedHashMap;
import java.util.List; import java.util.List;
@ -70,11 +73,13 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
private boolean dtr = false; private boolean dtr = false;
private boolean rts = false; private boolean rts = false;
private final boolean mEnableAsyncReads;
private UsbEndpoint mReadEndpoint; private UsbEndpoint mReadEndpoint;
private UsbEndpoint mWriteEndpoint; private UsbEndpoint mWriteEndpoint;
public Ch340SerialPort(UsbDevice device, int portNumber) { public Ch340SerialPort(UsbDevice device, int portNumber) {
super(device, portNumber); super(device, portNumber);
mEnableAsyncReads = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1);
} }
@Override @Override
@ -112,6 +117,11 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
} }
} }
if (mEnableAsyncReads) {
Log.d(TAG, "Async reads enabled");
} else {
Log.d(TAG, "Async reads disabled.");
}
initialize(); initialize();
setBaudRate(DEFAULT_BAUD_RATE); setBaudRate(DEFAULT_BAUD_RATE);
@ -146,6 +156,32 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
@Override @Override
public int read(byte[] dest, int timeoutMillis) throws IOException { public int read(byte[] dest, int timeoutMillis) throws IOException {
if (mEnableAsyncReads) {
final UsbRequest request = new UsbRequest();
try {
request.initialize(mConnection, mReadEndpoint);
final ByteBuffer buf = ByteBuffer.wrap(dest);
if (!request.queue(buf, dest.length)) {
throw new IOException("Error queueing request.");
}
final UsbRequest response = mConnection.requestWait();
if (response == null) {
throw new IOException("Null response");
}
final int nread = buf.position();
if (nread > 0) {
//Log.d(TAG, HexDump.dumpHexString(dest, 0, Math.min(32, dest.length)));
return nread;
} else {
return 0;
}
} finally {
request.close();
}
}
final int numBytesRead; final int numBytesRead;
synchronized (mReadBufferLock) { synchronized (mReadBufferLock) {
int readAmt = Math.min(dest.length, mReadBuffer.length); int readAmt = Math.min(dest.length, mReadBuffer.length);