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Code Issues Releases Wiki Activity

add dedicated handling for Ch34x baud rate 921600

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This commit is contained in:
kai-morich
2021-07-28 17:40:17 +02:00
parent 76f0260a55
commit 18e300efa3
2 changed files with 60 additions and 17 deletions
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usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/Ch34xSerialDriver.java
+28 -15
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@@ -10,6 +10,9 @@ import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbEndpoint;
import android.hardware.usb.UsbInterface;
import android.util.Log;
import com.hoho.android.usbserial.BuildConfig;
import java.io.IOException;
import java.util.Collections;
@@ -191,29 +194,39 @@ public class Ch34xSerialDriver implements UsbSerialDriver {
private void setBaudRate(int baudRate) throws IOException {
final long CH341_BAUDBASE_FACTOR = 1532620800;
final int CH341_BAUDBASE_DIVMAX = 3;
long factor;
long divisor;
long factor = CH341_BAUDBASE_FACTOR / baudRate;
int divisor = CH341_BAUDBASE_DIVMAX;
if (baudRate == 921600) {
divisor = 7;
factor = 0xf300;
} else {
final long BAUDBASE_FACTOR = 1532620800;
final int BAUDBASE_DIVMAX = 3;
while ((factor > 0xfff0) && divisor > 0) {
factor >>= 3;
divisor--;
}
if (factor > 0xfff0) {
throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
if(BuildConfig.DEBUG && (baudRate & (3<<29)) == (1<<29))
baudRate &= ~(1<<29); // for testing purpose bypass dedicated baud rate handling
factor = BAUDBASE_FACTOR / baudRate;
divisor = BAUDBASE_DIVMAX;
while ((factor > 0xfff0) && divisor > 0) {
factor >>= 3;
divisor--;
}
if (factor > 0xfff0) {
throw new UnsupportedOperationException("Unsupported baud rate: " + baudRate);
}
factor = 0x10000 - factor;
}
factor = 0x10000 - factor;
divisor |= 0x0080; // else ch341a waits until buffer full
int ret = controlOut(0x9a, 0x1312, (int) ((factor & 0xff00) | divisor));
int val1 = (int) ((factor & 0xff00) | divisor);
int val2 = (int) (factor & 0xff);
Log.d(TAG, String.format("baud rate=%d, 0x1312=0x%04x, 0x0f2c=0x%04x", baudRate, val1, val2));
int ret = controlOut(0x9a, 0x1312, val1);
if (ret < 0) {
throw new IOException("Error setting baud rate: #1)");
}
ret = controlOut(0x9a, 0x0f2c, (int) (factor & 0xff));
ret = controlOut(0x9a, 0x0f2c, val2);
if (ret < 0) {
throw new IOException("Error setting baud rate: #2");
}