Atmel Evaluation Kit AT91SAM9G25-EK AT91SAM9G25-EK Data Sheet
Product codes
AT91SAM9G25-EK
707
SAM9G25 [DATASHEET]
11032C–ATARM–25-Jan-13
37.7
Functional Description
37.7.1 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
acknowledgement. The number of bytes per transfer is unlimited (see
Each transfer begins with a START condition and terminates with a STOP condition (see
z
A high-to-low transition on the TWD line while TWCK is high defines the START condition.
z
A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.
Figure 37-3. START and STOP Conditions
Figure 37-4. Transfer Format
37.7.2 Modes of Operation
The TWI has different modes of operations:
z
Master transmitter mode
z
Master receiver mode
z
Multi-master transmitter mode
z
Multi-master receiver mode
z
Slave transmitter mode
z
Slave receiver mode
These modes are described in the following chapters.
TWD
TWCK
Start
Stop
TWD
TWCK
Start
Address
R/W
Ack
Data
Ack
Data
Ack
Stop