Datasheet

223
AT32UC3A
24.7.3 Interrupt
The TWI interface has an interrupt line connected to the Interrupt Controller (INTC). In order to
handle interrupts, the INTC must be programmed before configuring the TWI.
24.8 Functional Description
24.8.1 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
24-4).
Each transfer begins with a START condition and terminates with a STOP condition (see Figure
24-3).
• 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 24-3. START and STOP Conditions
Figure 24-4. Transfer Format
24.9 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.
TWD
TWCK
Start Stop
TWD
TWCK
Start Address R/W Ack Data Ack Data Ack Stop
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AVR32-01/12