@ohos.usbManager.serial (Serial Port Management)

This module provides the serial port management functions, including enabling and disabling the serial port of the device, writing and reading data, setting and obtaining the configuration parameters of the serial port, and managing permissions.

NOTE

The initial APIs of this module are supported since API version 18. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import { serialManager } from '@kit.BasicServicesKit';

serialManager.getPortList

getPortList(): Readonly<serialport>[];

Obtains the serial port device list, including the device name and port number.

System capability: SystemCapability.USB.USBManager.Serial

Returns

Type	Description
Readonly<SerialPort>[]	Serial port information list.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port device list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

serialManager.hasSerialRight

hasSerialRight(portId: number): boolean;

Checks whether the application has the permission to access the serial port device. When an application is restarted after exiting, you need to request the permission from the user again.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.

Returns

Type	Description
boolean	The value true indicates that the permission is authorized, and false indicates the opposite.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
14400005	Database operation exception.
31400001	Serial port management exception.
31400003	Device does not exist.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('portList: ', JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (serialManager.hasSerialRight(portId)) {
  console.info('The serial port is accessible');
} else {
  console.info('No permission to access the serial port');
}

serialManager.requestSerialRight

requestSerialRight(portId: number): Promise<boolean>

Requests the permission for the application to access the serial port device. After the application exits, the access permission on the serial port device is automatically removed. After the application is restarted, you need to request the permission again.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.

Returns

Type	Description
Promise<boolean>	Promise used to return the result. The value true indicates that the permission is successfully requested, and false indicates the opposite.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
14400005	Database operation exception.
31400001	Serial port management exception.
31400003	Device does not exist.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

serialManager.open

open(portId: number): void;

Opens a serial port device.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400002	Access denied. Call requestSerialRight to request user authorization first.
31400003	Device does not exist.
31400004	The serial port device is occupied.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

serialManager.getAttribute

getAttribute(portId: number): Readonly<SerialAttribute>;

Obtains the configuration parameters of a specified serial port.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.

Returns

Type	Description
Readonly<SerialAttribute>	Configuration parameters of the serial port.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Obtain the serial port configuration.
try {
  let attribute: serialManager.SerialAttribute = serialManager.getAttribute(portId);
  if (attribute === undefined) {
    console.error('getAttribute usbSerial error, attribute is undefined');
  } else {
    console.info('getAttribute usbSerial success, attribute: ' + JSON.stringify(attribute));
  }
} catch (error) {
  console.error('getAttribute usbSerial error, ' + JSON.stringify(error));
}

serialManager.setAttribute

setAttribute(portId: number, attribute: SerialAttribute): void;

Sets the parameters of the serial port. If this method is not called, the default configuration parameters are used (baud rate: 9600 bit/s; data bit: 8; parity bit: 0; stop bit: 1).

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.
attribute	SerialAttribute	Yes	Configuration parameters of the serial port.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Set the serial port configuration.
try {
  let attribute: serialManager.SerialAttribute = {
    baudRate: serialManager.BaudRates.BAUDRATE_9600,
    dataBits: serialManager.DataBits.DATABIT_8,
    parity: serialManager.Parity.PARITY_NONE,
    stopBits: serialManager.StopBits.STOPBIT_1
  }
  serialManager.setAttribute(portId, attribute);
  console.info('setAttribute usbSerial success, attribute: ' + JSON.stringify(attribute));
} catch (error) {
  console.error('setAttribute usbSerial error, ' + JSON.stringify(error));
}

serialManager.read

read(portId: number, buffer: Uint8Array, timeout?: number): Promise<number>;

Reads data from the serial port device asynchronously.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.
buffer	Uint8Array	Yes	Buffer for reading data.
timeout	number	No	Timeout duration for reading data, in milliseconds.

Returns

Type	Description
Promise<number>	Promise used to return the length of the data read.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.
31400006	Data transfer timed out.
31400007	I/O exception.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Read data asynchronously.
let readBuffer: Uint8Array = new Uint8Array(64);
serialManager.read(portId, readBuffer, 2000).then((size: number) => {
  console.info('read usbSerial success, readBuffer: ' + readBuffer.toString());
}).catch((error: Error) => {
  console.error('read usbSerial error, ' + JSON.stringify(error));
})

serialManager.readSync

readSync(portId: number, buffer: Uint8Array, timeout?: number): number;

Reads data from the serial port device synchronously.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.
buffer	Uint8Array	Yes	Buffer for reading data.
timeout	number	No	Timeout duration for reading data, in milliseconds.

Returns

Type	Description
number	Length of the data read.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.
31400006	Data transfer timed out.
31400007	I/O exception.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Read data synchronously.
let readSyncBuffer: Uint8Array = new Uint8Array(64);
try {
  serialManager.readSync(portId, readSyncBuffer, 2000);
  console.info('readSync usbSerial success, readSyncBuffer: ' + readSyncBuffer.toString());
} catch (error) {
  console.error('readSync usbSerial error, ' + JSON.stringify(error));
}

serialManager.write

write(portId: number, buffer: Uint8Array, timeout?: number): Promise<number>;

Writes data to the serial port device asynchronously.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.
buffer	Uint8Array	Yes	Buffer for writing data.
timeout	number	No	Timeout duration for writing data, in milliseconds.

Returns

Type	Description
Promise<number>	Promise used to return the length of the data written.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.
31400006	Data transfer timed out.
31400007	I/O exception.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Write data asynchronously.
let writeBuffer: Uint8Array = new Uint8Array(buffer.from('Hello World', 'utf-8').buffer)
serialManager.write(portId, writeBuffer, 2000).then((size: number) => {
  console.info('write usbSerial success, writeBuffer: ' + writeBuffer.toString());
}).catch((error: Error) => {
  console.error('write usbSerial error, ' + JSON.stringify(error));
})

serialManager.writeSync

writeSync(portId: number, buffer: Uint8Array, timeout?: number): number;

Writes data to the serial port device synchronously.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.
buffer	Uint8Array	Yes	Destination buffer for writing data.
timeout	number	No	Timeout duration for writing data, in milliseconds.

Returns

Type	Description
number	Length of the data written.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.
31400006	Data transfer timed out.
31400007	I/O exception.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Write data synchronously.
let writeSyncBuffer: Uint8Array = new Uint8Array(buffer.from('Hello World', 'utf-8').buffer)
try {
  serialManager.writeSync(portId, writeSyncBuffer, 2000);
  console.info('writeSync usbSerial success, writeSyncBuffer: ' + writeSyncBuffer.toString());
} catch (error) {
  console.error('writeSync usbSerial error, ' + JSON.stringify(error));
}

serialManager.close

close(portId: number): void;

Closes the serial port device.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
31400001	Serial port management exception.
31400003	Device does not exist.
31400005	The serial port device is not opened. Call the open API first.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Open a serial port device.
try {
  serialManager.open(portId)
  console.info('open usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('open usbSerial error, ' + JSON.stringify(error));
}

// Close the serial port device.
try {
  serialManager.close(portId);
  console.info('close usbSerial success, portId: ' + portId);
} catch (error) {
  console.error('close usbSerial error, ' + JSON.stringify(error));
}

serialManager.cancelSerialRight

cancelSerialRight(portId: number): void;

Cancels the permission to access the serial port device when the application is running. This API is used to close the enabled serial port device.

System capability: SystemCapability.USB.USBManager.Serial

Parameters

Name	Type	Mandatory	Description
portId	number	Yes	Port number.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified; 2. Incorrect parameter types; 3. Parameter verification failed.
14400005	Database operation exception.
31400001	Serial port management exception.
31400002	Access denied. Call requestSerialRight to request user authorization first.
31400003	Device does not exist.

Example

import { JSON } from '@kit.ArkTS';
import { serialManager } from '@kit.BasicServicesKit';

// Obtain the serial port list.
let portList: serialManager.SerialPort[] = serialManager.getPortList();
console.info('usbSerial portList: ' + JSON.stringify(portList));
if (portList === undefined||portList.length === 0) {
  console.info('usbSerial portList is empty');
  return;
}
let portId: number = portList[0].portId;

// Check whether the device can be accessed by the application.
if (!serialManager.hasSerialRight(portId)) {
  await serialManager.requestSerialRight(portId).then(result => {
    if (!result) {
      // If the application does not have the access permission and is not granted by the user, the application exits.
      console.info('user is not granted the operation  permission');
      return;
    } else {
      console.info('grant permission successfully');
    }
  });
}

// Cancel the granted permission.
try {
  serialManager.cancelSerialRight(portId);
  console.info('cancelSerialRight success, portId: ', portId);
} catch (error) {
  console.error('cancelSerialRight error, ', JSON.stringify(error));
}

SerialAttribute

Represents the configuration parameters of a serial port.

System capability: SystemCapability.USB.USBManager.Serial

Name	Type	Mandatory	Description
baudrate	number	Yes	Baud rate.
dataBits	number	No	Data bit.
parity	number	No	Parity check.
stopBits	number	No	Stop bit.

SerialPort

Represents the parameters of a serial port.

System capability: SystemCapability.USB.USBManager.Serial

Name	Type	Mandatory	Description
portId	number	Yes	Port number.
deviceName	string	Yes	Serial port device name.

BaudRates

Enumerates the baud rates.

System capability: SystemCapability.USB.USBManager.Serial

Name	Value	Description
BAUDRATE_50	50	The baud rate is 50 bit/s.
BAUDRATE_75	75	The baud rate is 75 bit/s.
BAUDRATE_110	110	The baud rate is 110 bit/s.
BAUDRATE_134	134	The baud rate is 134 bit/s.
BAUDRATE_150	150	The baud rate is 150 bit/s.
BAUDRATE_200	200	The baud rate is 200 bit/s.
BAUDRATE_300	300	The baud rate is 300 bit/s.
BAUDRATE_600	600	The baud rate is 600 bit/s.
BAUDRATE_1200	1200	The baud rate is 1200 bit/s.
BAUDRATE_1800	1800	The baud rate is 1800 bit/s.
BAUDRATE_2400	2400	The baud rate is 2400 bit/s.
BAUDRATE_4800	4800	The baud rate is 4800 bit/s.
BAUDRATE_9600	9600	The baud rate is 9600 bit/s.
BAUDRATE_19200	19200	The baud rate is 19200 bit/s.
BAUDRATE_38400	38400	The baud rate is 38400 bit/s.
BAUDRATE_57600	57600	The baud rate is 57600 bit/s.
BAUDRATE_115200	115200	The baud rate is 115200 bit/s.
BAUDRATE_230400	230400	The baud rate is 230400 bit/s.
BAUDRATE_460800	460800	The baud rate is 460800 bit/s.
BAUDRATE_500000	500000	The baud rate is 500000 bit/s.
BAUDRATE_576000	576000	The baud rate is 576000 bit/s.
BAUDRATE_921600	921600	The baud rate is 921600 bit/s.
BAUDRATE_1000000	1000000	The baud rate is 1000000 bit/s.
BAUDRATE_1152000	1152000	The baud rate is 1152000 bit/s.
BAUDRATE_1500000	1500000	The baud rate is 1500000 bit/s.
BAUDRATE_2000000	2000000	The baud rate is 2000000 bit/s.
BAUDRATE_2500000	2500000	The baud rate is 2500000 bit/s.
BAUDRATE_3000000	3000000	The baud rate is 3000000 bit/s.
BAUDRATE_3500000	3500000	The baud rate is 3500000 bit/s.
BAUDRATE_4000000	4000000	The baud rate is 4000000 bit/s.

DataBits

Enumerates the number of data bits.

System capability: SystemCapability.USB.USBManager.Serial

Name	Value	Description
DATABIT_8	8	The number of data bits is 8.
DATABIT_7	7	The number of data bits is 7.
DATABIT_6	6	The number of data bits is 6.
DATABIT_5	5	The number of data bits is 5.

Parity

Enumerates the parity check modes.

System capability: SystemCapability.USB.USBManager.Serial

Name	Value	Description
PARITY_NONE	0	No parity.
PARITY_ODD	1	Odd parity.
PARITY_EVEN	2	Even parity.
PARITY_MARK	3	Mark parity, whose parity bit is fixed at 1.
PARITY_SPACE	4	Space parity, whose parity bit is fixed at 0.

StopBits

Enumerates of the number of stop bits.

System capability: SystemCapability.USB.USBManager.Serial

Name	Value	Description
STOPBIT_1	0	The number of stop bits is 1.
STOPBIT_1P5	1	The number of stop bits is 1.5.
STOPBIT_2	2	The number of stop bits is 2.

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