DEMOKITCRX14 STMicroelectronics, DEMOKITCRX14 Datasheet - Page 18

• Manufacturer Part Number: DEMOKITCRX14
• Description: RFID EVALUATION KIT ISO14443-B
• Manufacturer: STMicroelectronics
• Type: Development kitr

Specifications of DEMOKITCRX14

• Contents: CD-ROM, CRX14 Board, USB Transceiver, Samples and Documentation
• Processor To Be Evaluated: CRX14
• Interface Type: I2C
• Operating Supply Voltage: 5 V
• For Use With/related Products: CRX14
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 497-3704

CRX14
I²C Input/Output Frame Register Protocol
Figure 14.
frame command of N Bytes into the Input/Output
Frame Register.
After the I²C STOP condition, the request frame is
RF transmitted in the ISO14443 type-B format.
The CRX14 then waits for the PICC answer frame
which will also be stored in the Input/Output Frame
Register. The request frame is over-written by the
answer frame.
Figure 15.
swer frame.
Figure 14. Host-to-CRX14 Transfer: I²C Write to Input/Output Frame Register for ISO14443B
Figure 15. CRX14-to-Host Transfer: I²C Random Address Read
from Input/Output Frame Register for ISO14443B
Figure 16. CRX14-to-Host Transfer: I²C Current Address Read
from I/O Frame Register for ISO14443B
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CRX14
Master
Bus
Master
CRX14
Read
Bus
Slave
Slave
Write
Bus
Bus
Bus Master
CRX14 Write
Bus Slave
S
T
A
R
T
S
T
A
R
T
1 0 1 0XXX
1 0 1 0 XX X
shows how to read an N-Byte PICC an-
shows how to store a PICC request
Device
Select
Code
Device
Select
Code
S
T
A
R
T
1 0 1 0 XX X
R/W
Device
Select
Code
ACK
R/W
Input/Output
ACK
Register
Address
Input/Output
01h
R/W
Register
Address
ACK
01h
ACK
Frame Length
Received
R
E
S
T
A
R
T
1 0 1 0 XXX
ACK
N
Device
Select
Code
Request Frame
Length N
ACK
R/W
N
ACK
Answer Frame
Received
Data 1
Data
Length
ACK
Frame
N
Command
ACK
PICC
Code
Data 1
ACK
The two CRC Bytes generated by the PICC are
not stored.
The CRX14 continues to output data Bytes until a
NoACK has been generated by the I²C Host, and
received by the CRX14. After all 36 Bytes have
been output, the CRX14 “rolls over”, and starts
outputting from the start of the Input/Output Frame
Register again.
The CRX14 supports the I²C Current Address and
Random Address Read modes. The Current Ad-
dress Read mode can be used if the previous
command was issued to the register where the
Read is to take place.
Answer Frame
Answer
Data1
Frame
Data 2
Data
Data
ACK
Command
Parameter
ACK
Data 2
ACK
PICC
Answer Frame
Answer
Frame
Data 2
Data
Data
ACK
ACK
Command
Parameter
ACK
PICC
Answer
Frame
Data
Answer Frame
Data N
Data
ACK
ACK
Command
Parameter
Data N
Answer
Frame
NoACK
PICC
Data N
Data
S
T
O
P
NoACK
ai09243
ai09245
ai09243
ACK
S
T
O
P
S
T
O
P