Datasheet

708
42023E–SAM–07/2013
ATSAM4L8/L4/L2
27.8 Functional Description
27.8.1 Transfer Format
The data put on the TWD line must be 8 bits long. Data is transferred MSB first; each byte must
be followed by an acknowledgement. The number of bytes per transfer is unlimited (see Figure
27-4).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure
27-4).
• A high-to-low transition on the TWD line while TWCK is high defines the START condition.
• A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 27-3. START and STOP Conditions
Figure 27-4. Transfer Format
27.8.2 Operation
The TWIM has two modes of operation:
• Master transmitter mode
• Master receiver mode
The master is the device which starts and stops a transfer and generates the TWCK clock.
These modes are described in the following chapters.
TWD
TWCK
Start Stop
TWD
TWCK
Start Address R/W Ack Data Ack Data Ack Stop