SAM3X8E Atmel Corporation, SAM3X8E Datasheet - Page 714

• Manufacturer Part Number: SAM3X8E
• Manufacturer: Atmel Corporation

33.6.3
33.7
33.7.1
33.7.2
714
714
Functional Description
SAM3X/A
SAM3X/A
Interrupt
Transfer Format
Modes of Operation
The TWI interface may be clocked through the Power Management Controller (PMC), thus the
programmer must first configure the PMC to enable the TWI clock.
The TWI interface has an interrupt line connected to the Nested Vector Interrupt Controller
(NVIC). In order to handle interrupts, the NVIC must be programmed before configuring the TWI.
Table 33-5.
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
33-4).
Each transfer begins with a START condition and terminates with a STOP condition (see
33-3).
Figure 33-3.
Figure 33-4. Transfer Format
The TWI has six modes of operations:
• 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.
• Master transmitter mode
• Master receiver mode
• Multi-master transmitter mode
• Multi-master receiver mode
Instance
TWI0
TWI1
TWD
TWCK
Peripheral IDs
START and STOP Conditions
Start
Address
TWCK
TWD
22
23
ID
R/W
Start
Ack
Data
Ack
Data
Stop
Ack
11057A–ATARM–17-Feb-12
11057A–ATARM–17-Feb-12
Stop
Figure
Figure