Used by the master to request bytes from a slave device. The bytes may then be retrieved with the available() and read() functions.

requestFrom() accepts a boolean argument (stop) changing its behavior for compatibility with certain I2C devices. If true, requestFrom() sends a stop message after the request, releasing the I2C bus. If false, requestFrom() sends a restart message after the request. The bus will not be released, which prevents another master device from requesting between messages. This allows one master device to send multiple requests while in control. The default value is true.


Wire.requestFrom(address, quantity)
Wire.requestFrom(address, quantity, stop)


address: the 7-bit address of the device to request bytes from
quantity: the number of bytes to request
stop: boolean. true will send a stop message after the request, releasing the bus. false will continually send a restart after the request, keeping the connection active.


byte : the number of bytes returned from the slave device

See also


Libraries Reference Home

The text of the 86Duino reference is a modification of the Arduino reference, and is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.