at32uc3b0512-z2ues ATMEL Corporation, at32uc3b0512-z2ues Datasheet - Page 223

• Manufacturer Part Number: at32uc3b0512-z2ues
• Description: 32-bit Avr Microcontroller
• Manufacturer: ATMEL Corporation

19.7.3
19.8
19.8.1
19.9
32059J–12/2010
Functional Description
Modes of Operation
Interrupt
Transfer Format
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.
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
19-4).
Each transfer begins with a START condition and terminates with a STOP condition (see
19-3).
• 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 19-3.
Figure 19-4. Transfer Format
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 and STOP Conditions
Start
Address
TWCK
TWD
R/W
Start
Ack
Data
Ack
Data
Stop
AT32UC3B
Ack
Stop
Figure
Figure
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