CR14 STMicroelectronics, CR14 Datasheet - Page 22

• 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
5
5.1
Figure 11. CR14-to-Host Transfer: I²C Random Address Read from Parameter Register
22/46
CR14 Read
Bus Master
Bus Slave
Applying the I²C protocol to the CR14 registers
I²C Parameter Register Protocol
Figure 10
active after the I²C STOP condition.
Figure 11
the Parameter Register contents until it receives a NoACK from the I²C Host.
The CR14 supports the I²C Current Address and Random Address Read modes. The Current
Address Read mode can be used if the previous command was issued to the register where the
Read is to take place.
Figure 10. Host-to-CR14 Transfer: I²C Write to Parameter Register
Figure 12. CR14-to-Host Transfer: I²C Current Address Read from Parameter Register
S
T
A
R
T
1 0 1 0 X X X
CR14 Write
shows how new data is written to the Parameter Register. The new value becomes
shows how to read the Parameter Register contents. The CR14 sends and re-sends
Bus Master
Device Select
Bus Slave
Code
CR14 Read
Bus Master
Bus Slave
S
T
A
R
T
R/W
ACK
1 0 1 0 X X X
Device Select
Parameter Register
S
T
A
R
T
Code
1 0 1 0 X X X
Address
Device Select
00h
Code
R/W
ACK
ACK
Parameter Register
R/W
R
E
S
T
A
R
T
ACK
Address
1 0 1 0 X X X
00h
Device Select
Register Byte
Code
data
Value
ACK
R/W
NoACK
ACK
Register Byte
data
Value
S
T
O
P
Register Byte
data
Value
ACK
ai12040
S
T
O
P
NoACK
ai12038
ai12039
CR14
S
T
O
P