Datasheet

501
SAM9G45 [DATASHEET]
Atmel-6438O-ATARM-SAM9G45-Datasheet_08-Dec-15
30.6.3 Interrupt
The TWI interface has an interrupt line connected to the Advanced Interrupt Controller (AIC). In order to handle
interrupts, the AIC must be programmed before configuring the TWI.
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 sections.
Table 30-5. Peripheral IDs
Instance ID
TWI0 12
TWI1 13
TWD
TWCK
Start Stop
TWD
TWCK
Start Address R/W Ack Data Ack Data Ack Stop