Wire (Member Function Version)
Wire (using member functions)
Wire
Read/write as 2-wire serial (I2C) master (controller) (mwx::periph_wire)
Performs read/write operations as a 2-wire serial (I2C) master (controller).
Definition
Alias Definition
using TwoWire = mwx::periph_twowire<MWX_TWOWIRE_RCVBUFF>;
mwx::periph_wire<MWX_TWOWIRE_RCVBUFF> can be referenced as TwoWire.
Type Definitions
The following typedefs are used for argument and return types:
typedef uint8_t size_type;
typedef uint8_t value_type;
Notes
Some APIs do not strictly handle STOP bits.
In addition to this explanation, several argument types are defined for write() and writer::operator():
- Fixed-size array type
uint8_t cmds[]={11,12};...Wire.write(cmds); initializer_list<>typeWire.write({11,12})
Initialization and Termination
Creating a Wire instance
The instance and necessary initialization are handled within the library. In user code, call Wire.begin() to start using it.
When using the requestFrom() method, you can specify the size of a FIFO queue for temporary data storage. At compile time, set the number of bytes via the macro MWX_TWOWIRE_BUFF. The default is 32 bytes.
Example:
-DMWX_TWOWIRE_BUFF=16
begin()
void begin(
const size_type u8mode = WIRE_100KHZ,
bool b_portalt = false)
Initializes the hardware.
If you operate Wire without initialization, the TWELITE wireless module will hang.
When waking from sleep, if Wire was active just before sleep, it will restore its previous state.
| Parameter | Description |
|---|---|
u8mode | Specifies the bus frequency. Default is 100KHz (WIRE_CONF::WIRE_100KHZ).You can specify WIRE_CONF::WIRE_??KHZ where ?? can be 50, 66, 80, 100, 133, 160, 200, 266, 320, 400. |
b_portalt | Changes the hardware pin assignment. |
Example
void setup() {
...
Wire.begin();
...
}
void wakeup() {
...
Wire.begin();
...
}
Reading and Writing
There are two procedures for reading and writing. Use either as needed.
Member function version (using the member functions below for I/O)
requestFrom(), beginTransmission(), endTransmission(), write()Helper class version (stream functionality available)
reader, writer
Others
Probe (Device Presence Check)
bool probe(uint8_t address)
Checks if the device specified by address responds. Returns true if the device exists.
setClock()
void setClock(uint32_t speed)
This is intended to change the bus frequency, but it performs no action.