Datasheet

SAM9261 [DATASHEET]
Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16
394
30.7 Functional Description
30.7.1 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 30-4).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure 30-3).
 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 30-3. START and STOP Conditions
Figure 30-4. Transfer Format
30.7.2 Modes of Operation
The TWI has six modes of operations:
 Master transmitter mode
 Master receiver mode
 Multi-master transmitter mode
 Multi-master receiver mode
 Slave transmitter mode
 Slave receiver mode
These modes are described in the following chapters.
30.8 Master Mode
30.8.1 Definition
The Master is the device that starts a transfer, generates a clock and stops it.
TWD
TWCK
Start Stop
TWD
TWCK
Start Address R/W Ack Data Ack Data Ack Stop