Atmel SAM4L Xplained Pro Starter Kit Atmel ATSAM4L-XSTK ATSAM4L-XSTK 数据表
产品代码
ATSAM4L-XSTK
708
42023E–SAM–07/2013
ATSAM4L8/L4/L2
27.8
Functional Description
27.8.1
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
be followed by an acknowledgement. The number of bytes per transfer is unlimited (see
).
Each transfer begins with a START condition and terminates with a STOP condition (see
).
• 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 27-3. START and STOP Conditions
Figure 27-4. Transfer Format
27.8.2
Operation
The TWIM has two modes of operation:
• Master transmitter mode
• Master receiver mode
The master is the device which starts and stops a transfer and generates the TWCK clock.
These modes are described in the following chapters.
These modes are described in the following chapters.
TWD
TWCK
Start
Stop
TWD
TWCK
Start
Address
R/W
Ack
Data
Ack
Data
Ack
Stop