CR14 STMicroelectronics, CR14 Datasheet - Page 18

• Manufacturer Part Number: CR14
• Description: Low Cost Iso14443 Type-b Contactless Coupler Chip With Anti-collision And Crc Management
• Manufacturer: STMicroelectronics

4 CR14 I²C protocol description
4.5
18/46
Figure 6.
I²C Memory Addressing
To start up communication with the CR14, the bus master must initiate a START condition.
Then, the bus master sends 8 bits (with the most significant bit first) on the Serial Data line,
SDA. These bits consist of the Device Select Code (7 bits) plus a RW bit.
According to the I²C bus definition, the seven most significant bits of the Device Select Code
are the Device Type Identifier. For the CR14, these bits are defined as shown in
The 8th bit is the Read/Write bit (RW). It is set to ‘1’ for I²C Read, and to ‘0’ for I²C Write
operations.
If the data sent by the bus master matches the Device Select Code of a CR14 device, the
corresponding device returns an acknowledgment on the SDA bus during the 9
The CR14 devices whose Device Select Codes do not correspond to the data sent, generate a
No-ACK. They deselect themselves from the bus and go into stand-by mode.
SCL
SDA
SCL
SDA
SCL
SDA
CONDITION
I²C Bus Protocol
START
CONDITION
START
MSB
1
MSB
1
2
2
INPUT
SDA
3
3
CHANGE
SDA
7
7
8
8
ACK
9
ACK
CONDITION
9
th
STOP
CONDITION
Table
bit time.
STOP
AI00792
6.
CR14