CR14 STMicroelectronics, CR14 Datasheet - Page 24

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

5 Applying the I²C protocol to the CR14 registers
Figure 15. CR14-to-Host Transfer: I²C Current Address Read from I/O Frame Register
5.3
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Bus Master
Bus Slave
CR14 Write
I²C Slot Marker Register Protocol
An I²C Write command to the Slot Marker Register generates an automated sixteen-command
loop (See
All the answers from the ST short range memory devices that are detected, are written in the
Input/Output Frame Register.
Read from the I²C Slot Marker Register is not supported by the CR14. If the I²C Host tries to
read the Slot Marker Register, the CR14 will return the data value FFh in both Random Address
and Current Address Read modes until NoACK is generated by the I²C Host.
The result of the detection sequence is stored in the Input/Output Frame Register. This
Register can be read by the host by using I²C Random Address Read.
Figure 16. Host-to-CR14 Transfer: I²C Write to Slot Marker Register
for ISO14443B
S
T
A
R
T
1 0 1 0 XX X
Device
Select
Code
Figure 16
CR14 Write
Bus Master
R/W
Bus Slave
ACK
for a description of the command).
Frame Length
Received
N
S
T
A
R
T
ACK
1 0 1 0 X X X
Answer Frame
Device Select
Data 1
Data
Code
ACK
Answer Frame
R/W
ACK
Data 2
Data
Slot Marker
Register
Address
ACK
03h
Answer Frame
Data
ACK
ACK
S
T
O
P
Answer Frame
Data N
Data
ai12044
NoACK
ai12043
S
T
O
P
CR14