BLERemoteCharacteristic Class

BLERemoteCharacteristic Class

Description
A class used for managing BLE GATT characteristics on connected remote devices.

Syntax
class BLERemoteCharacteristic

Members

Public Constructors
No public constructor is available for this class. You can get a pointer to an instance of this class using BLERemoteService::getCharacteristic().
Public Methods 
BLERemoteCharacteristic::getDescriptorGet a specific descriptor on the remote device
BLERemoteCharacteristic::getUUIDGet the characteristic UUID
BLERemoteCharacteristic::setBufferLenSet the size of the internal data buffer
BLERemoteCharacteristic::getBufferLenGet the current size of the internal data buffer
BLERemoteCharacteristic::canReadDetermine if characteristic has read property enabled
BLERemoteCharacteristic::canWriteDetermine if characteristic has write property enabled
BLERemoteCharacteristic::canNotifyDetermine if characteristic has notify property enabled
BLERemoteCharacteristic::canIndicateDetermine if characteristic has indicate property enabled
BLERemoteCharacteristic::getPropertiesGet the characteristic properties
BLERemoteCharacteristic::readStringRead the characteristic data buffer as a String object
BLERemoteCharacteristic::readData8Read the characteristic data buffer as an unsigned 8-bit integer
BLERemoteCharacteristic::readData16Read the characteristic data buffer as an unsigned 16-bit integer
BLERemoteCharacteristic::readData32Read the characteristic data buffer as an unsigned 32-bit integer
BLERemoteCharacteristic::writeStringWrite data to the characteristic as a String object or character array
BLERemoteCharacteristic::writeData8Write data to the characteristic as an unsigned 8-bit integer
BLERemoteCharacteristic::writeData16Write data to the characteristic as an unsigned 16-bit integer
BLERemoteCharacteristic::writeData32Write data to the characteristic as an unsigned 16-bit integer
BLERemoteCharacteristic::setDataWrite data to the characteristic
BLERemoteCharacteristic::getDataRead data from the characteristic
BLERemoteCharacteristic::enableNotifyIndicateEnable notification or indication for the characteristic
BLERemoteCharacteristic::disableNotifyIndicateDisable notification and indication for the characteristic
BLERemoteCharacteristic::setNotifyCallbackSet a user function as a notification callback

BLERemoteCharacteristic::getDescriptor

Description
Get a descriptor with the specified UUID on the remote device.

Syntax
BLERemoteDescriptor* getDescriptor(const char* uuid);
BLERemoteDescriptor* getDescriptor(BLEUUID uuid);

Parameters
uuid: the desired descriptor UUID, expressed as a character array or a BLEUUID object

Returns
The function returns the found descriptor as a BLERemoteDescriptor object pointer, otherwise nullptr is returned if a descriptor with the UUID is not found.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::getUUID

Description
Get the characteristic UUID.

Syntax
BLEUUID getUUID();

Parameters
The function requires no input parameter.

Returns
The function returns the characteristic UUID as a BLEUUID class object.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::setBufferLen

Description
Set the size of the internal data buffer of the characteristic.

Syntax
void setBufferLen(uint16_t max_len);

Parameters
max_len: number of bytes to resize the internal buffer to.

Returns
The function returns nothing.

Example Code
Example: BLEUartClient

Notes and Warnings
Characteristic data buffer has a default size of 20 bytes and can be increased up to 230 bytes.
 

BLERemoteCharacteristic::getBufferLen

Description
Get the size of the characteristic internal buffer.

Syntax
uint16_t getBufferLen();

Parameters
The function requires no input parameter.

Returns
The function returns the currently set internal buffer size.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::canRead

Description
Determine if characteristic has read property enabled.

Syntax
bool canRead();

Parameters
The function requires no input parameter.

Returns
The function returns TRUE if the read property for the characteristic is enabled.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::canWrite

Description
Determine if characteristic has write property enabled.

Syntax
bool canWrite();

Parameters
The function requires no input parameter.

Returns
The function returns TRUE if the write property for the characteristic is enabled.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::canNotify

Description
Determine if characteristic has notify property enabled.

Syntax
bool canNotify();

Parameters
The function requires no input parameter.

Returns
The function returns TRUE if the notify property for the characteristic is enabled.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::canIndicate

Description
Determine if characteristic has indicate property enabled.

Syntax
bool canIndicate();

Parameters
The function requires no input parameter.

Returns
The function returns TRUE if the indicate property for the characteristic is enabled.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::getProperties

Description
Get the characteristic properties.

Syntax
uint16_t getProperties();

Parameters
The function requires no input parameter.

Returns
The function returns the characteristic properties.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::readString

Description
Request for characteristic data from the remote device and read the data in the buffer, expressed as a String class object.

Syntax
String readString();

Parameters
The function requires no input parameter.

Returns
The function returns the data in the characteristic buffer expressed as a String class object.

Example Code
Example: BLEUartClient

Notes and Warnings
NA
 

BLERemoteCharacteristic::readData8

Description
Request for characteristic data from the remote device and read the data in the buffer, expressed as an unsigned 8-bit integer.

Syntax
uint8_t readData8();

Parameters
The function requires no input parameter.

Returns
The function returns the data in the characteristic buffer expressed as a uint8_t value.

Example Code
Example: BLEBatteryClient

Notes and Warnings
NA
 

BLERemoteCharacteristic::readData16

Description
Request for characteristic data from the remote device and read the data in the buffer, expressed as an unsigned 16-bit integer.

Syntax
uint16_t readData16();

Parameters
The function requires no input parameter.

Returns
The function returns the data in the characteristic buffer expressed as a uint16_t value.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::readData32

Description
Request for characteristic data from the remote device and read the data in the buffer, expressed as an unsigned 32-bit integer.

Syntax
uint32_t readData32();

Parameters
The function requires no input parameter.

Returns
The function returns the data in the characteristic buffer expressed as a uint32_t value.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::writeString

Description
Write data to the remote device characteristic as a String object or character array.

Syntax
bool writeString(String str);
bool writeString(const char* str);

Parameters
str: the data to write to the remote characteristic, expressed as a String class object or a char array.

Returns
The function returns TRUE if write data is successful.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::writeData8

Description
Write data to the remote device characteristic as an unsigned 8-bit integer.

Syntax
bool writeData8(uint8_t num);

Parameters
num: the data to write to the characteristic buffer expressed as an unsigned 8-bit integer.

Returns
The function returns TRUE if write data is successful.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::writeData16

Description
Write data to the remote device characteristic as an unsigned 16-bit integer.

Syntax
bool writeData16(uint16_t num);

Parameters
num: the data to write to the characteristic buffer expressed as an unsigned 16-bit integer.

Returns
The function returns TRUE if write data is successful.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::writeData32

Description
Write data to the remote device characteristic as a 32-bit integer.

Syntax
bool writeData32(uint32_t num);
bool writeData32(int num);

Parameters
num: the data to write to the characteristic buffer expressed as a 32-bit integer.

Returns
The function returns TRUE if write data is successful.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::setData

Description
Write data to the remote device characteristic.

Syntax
bool setData(uint8_t* data, uint16_t datalen);

Parameters
data: pointer to byte array containing desired data
datalen: number of bytes of data to write

Returns
The function returns TRUE if write data is successful.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::getData

Description
Request for characteristic data from the remote device and read the data in the buffer.

Syntax
uint16_t getData(uint8_t* data, uint16_t datalen);

Parameters
data: pointer to byte array to save data read from buffer
datalen: number of bytes of data to read

Returns
The function returns the number of bytes read.

Example Code
NA

Notes and Warnings
If the data buffer contains less data than requested, it will only read the available number of bytes of data.
 

BLERemoteCharacteristic::enableNotifyIndicate

Description
Enable the remote device to send notifications or indications for the characteristic.

Syntax
void enableNotifyIndicate(bool notify = 1);

Parameters
notify: TRUE to enable notifications, FALSE to enable indications.

Returns
The function returns nothing.

Example Code
Example: BLEUartClient

Notes and Warnings
NA
 

BLERemoteCharacteristic::disableNotifyIndicate

Description
Disable receiving notifications and indications for the characteristic from the remote device.

Syntax
void disableNotifyIndicate();

Parameters
The function requires no input parameter.

Returns
The function returns nothing.

Example Code
NA

Notes and Warnings
NA
 

BLERemoteCharacteristic::setNotifyCallback

Description
Set a user function to be called when the characteristic receives a notification from the remote device.

Syntax
void setNotifyCallback(void (*fCallback) (BLERemoteCharacteristic* chr, uint8_t* data, uint16_t length));

Parameters
fCallback: A user callback function that returns void and takes three arguments.
chr: pointer to BLERemoteCharacteristic object associated with notification.
data: pointer to byte array containing notification data.
length: number of bytes of notification data in array.

Returns
The function returns nothing.

Example Code
Example: BLEUartClient

Notes and Warnings
NA
 

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