Arduino - WireRequestFrom

Arduino

Reference Language | Libraries | Comparison | Changes

## Wire.requestFrom()

#### Description

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

As of Arduino 1.0.1, requestFrom() accepts a boolean argument 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.

#### Syntax

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

#### Parameters

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.

#### Returns

byte : the number of bytes returned from the slave device

#### See Also

- Wire.available()
- Wire.read()

Reference Home

Corrections, suggestions, and new documentation should be posted to the Forum.

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

### Share

### This link has expired.
Please re-subscribe to our Newsletters.

### Subscribe to our Newsletters

Email

Please enter a valid email to subscribe

Arduino Newsletter
Arduino Store Newsletter

### Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy

###### Newsletter

- ©2015 Arduino
- Copyright Notice
- Contact us
- About us
- Careers