Wire (Member Function Version)

Wire (using member functions)

This method using member functions has relatively low abstraction and follows a general API structure similar to that provided by C language libraries. It offers a more intuitive procedure for operating a two-wire serial bus.

However, you need to explicitly manage the start and end of bus usage.

Reading

`requestFrom()`

size_type requestFrom(
    uint8_t u8address,
    size_type length,
    bool b_send_stop = true)

Reads a specified number of bytes in one operation. The result is stored in a queue, so you should call the .read() method repeatedly until the queue is empty immediately afterward.

Parameter	Description
`u8address`	I2C address to read from
`length`	Number of bytes to read
`b_send_stop=true`	If `true`, a STOP bit is issued at the end of reading
Return type `size_type`	Number of bytes read. `0` indicates failure

Code Example

int len = Wire.requestFrom(0x70, 6);
for (int i = 0; i < 6; i++) {
  if (Wire.available()) {
    au8data[i] = Wire.read();
    Serial.print(buff[i], HEX);
  }
}
// skip the rest (just in case)
// while (Wire.available()) Wire.read(); // normally, not necessary.

Writing

The writing process starts with beginTransmission(), then proceeds with the write() method. After the entire write operation is complete, call endTransmission().

#define DEV_ADDR (0x70)
const uint8_t msg[2] =
  {SHTC3_SOFT_RST_H, SHTC3_SOFT_RST_L};

Wire.beginTransmission(DEV_ADDR);
Wire.write(msg, sizeof(msg));
Wire.endTransmission();

`beginTransmission()`

void beginTransmission(uint8_t address)

Initializes a write transfer. After the write process, call endTransmission() promptly.

Parameter	Description
`u8address`	I2C address to write to

`write(value)`

size_type write(const value_type value)

Writes a single byte.

Parameter	Description
`value`	Byte to write
Return `size_type`	Number of bytes written. `0` indicates an error.

`write(*value, quantity)`

size_type write(
  const value_type* value,
  size_type quantity)

Writes a sequence of bytes.

Parameter	Description
`*value`	Byte sequence to write
`size_type`	Number of bytes
Return `size_type`	Number of bytes written. `0` indicates an error.

`endTransmission()`

uint8_t endTransmission(bool sendStop = true)

Finalizes the write operation.

Parameter	Description
`sendStop = true`	Issues a STOP bit
Return `uint8_t`	0: success, 4: failure