TwoWire Class
TwoWire Class
Description
A class of I2C API.
Syntax
class TwoWire
Members
| Public Constructors | |
| TwoWire::TwoWire | Constructs a TwoWire object. |
| Public Methods | |
| TwoWire::begin | Initialize I2C master/slave. |
| TwoWire::setClock | Set I2C clock frequency. |
| TwoWire::beginTransmission | Begin I2C transmission. |
| TwoWire::endTransmission | Stop I2C transmission. |
| TwoWire::requestFrom | Set I2C requestFrom. |
| TwoWire::write | Write data to I2C. |
| TwoWire::available | Check if I2C is available. |
| TwoWire::read | Read data from I2C. |
| TwoWire::peek | Read peek from I2C. |
| TwoWire::flush | Do nothing, use, and transmission(..) to force data transfer. |
| TwoWire::onReceive | Callback function when I2C on receive. |
| TwoWire::onRequest | Callback function when I2C on request. |
TwoWire::TwoWire
Description
Constructs a TwoWire object.
Syntax
TwoWire(uint32_t dwSDAPin, uint32_t dwSCLPin);
Parameters
dwSDAPin: The pin number on Ameba board to be set as SDA pin.
dwSCLPin: The pin number on Ameba board to be set as SCL pin.
Returns
NA
Example Code
Example: MasterWriter
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_writer/master_writer.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::begin
Description
Initialize I2C master/slave.
Syntax
void begin(void);
void begin(uint8_t address = 0);
void begin(int address);
Parameters
address: Set the I2C master mode with slave address value.
Returns
NA
Example Code
Example: MasterWriter
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_writer/master_writer.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::setClock
Description
Set I2C clock frequency.
Syntax
void setClock(uint32_t frequency);
Parameters
frequency: The frequency values.
Returns
NA
Example Code
Example: MasterWriter
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_writer/master_writer.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::beginTransmission
Description
Begin I2C transmission to device.
Syntax
void beginTransmission(uint8_t address);
void beginTransmission(int address);
Parameters
address: The transmission address.
Returns
NA
Example Code
Example: MasterWriter
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_writer/master_writer.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::endTransmission
Description
Stop I2C transmission.
Syntax
uint8_t endTransmission(uint8_t sendStop);
uint8_t endTransmission(void);
Parameters
sendStop: True to end the transmission.
Returns
This function returns 0 if successful, else returns error.
Example Code
Example: MasterWriter
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_writer/master_writer.ino)
Notes and Warnings
Originally, ‘endTransmission’ was an f(void) function. It has been modified to take one parameter indicating whether a STOP should be performed on the bus. Calling endTransmission(false) allows a sketch to perform a repeated start.
WARNING: Nothing in the library keeps track of whether the bus tenure has been properly ended with a STOP. It is very possible to leave the bus in a hung state if no call to endTransmission(true) is made. Some I2C devices will behave oddly if they do not see a STOP.
If the input parameter is void, this provides backward compatibility with the original definition, and expected behavior, of endTransmission.
“Wire.h” must be included to use the class function.
TwoWire::requestFrom
Description
Set I2C requestFrom.
Syntax
uint8_t requestFrom(uint8_t address, uint8_t quantity, uint8_t sendStop);
uint8_t requestFrom(uint8_t address, uint8_t quantity);
uint8_t requestFrom(int address, int quantity);
uint8_t requestFrom(int address, int quantity, int sendStop);
Parameters
address: I2C read address.
quantity: I2C read quantity.
sendStop: True to end the transmission.
Returns
This function returns 0 if successful, else returns error.
Example Code
Example: MasterReader
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_reader/master_reader.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::write
Description
Write data to I2C.
Syntax
size_t write(uint8_t data);
size_t write(const uint8_t *data, size_t quantity);
Parameters
data: The data to be transmitted.
quantity: The quantity of data.
Returns
This function returns 0 if successful, else returns error.
Example Code
Example: MasterWriter
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_writer/master_writer.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::available
Description
Check if I2C is available.
Syntax
virtual int available(void);
Parameters
NA
Returns
This function returns 0 if successful, else returns error.
Example Code
Example: MasterReader
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_reader/master_reader.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::read
Description
Read data from I2C.
Syntax
virtual int read(void);
Parameters
NA
Returns
This function returns the data read from receiver buffer.
Example Code
Example: MasterReader
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_reader/master_reader.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::peek
Description
Read peek from I2C.
Syntax
virtual int peek(void);
Parameters
NA
Returns
This function returns the peek data read from receiver buffer.
Example Code
Example: MasterReader
(https://github.com/ambiot/amb1_arduino/blob/dev/Arduino_package/hardware/libraries/Wire/examples/master_reader/master_reader.ino)
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::flush
Description
Do nothing, use endTransmission(..) to force data transfer.
Syntax
virtual void flush(void);
Parameters
NA
Returns
NA
Example Code
NA
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::onReceive
Description
Callback function when I2C is on receive.
Syntax
void onReceive(void(*function)(int));
Parameters
function: The callback function.
Returns
NA
Example Code
NA
Notes and Warnings
“Wire.h” must be included to use the class function.
TwoWire::onRequest
Description
Callback function when I2C is on request.
Syntax
void onRequest(void(*function)(void));
Parameters
function: The callback function.
Returns
NA
Example Code
NA
Notes and Warnings
“Wire.h” must be included to use the class function.
