DEMOKITCRX14 STMicroelectronics, DEMOKITCRX14 Datasheet - Page 23

• 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
5.2
Figure 13. Host-to-CRX14 transfer: I²C write to I/O frame register for ISO14443B
Figure 14. CRX14-to-host transfer: I²C random address read from I/O frame register for
Bus
Master
CRX14
Read
Bus
Slave
CRX14
Master
Slave
Write
Bus
Bus
S
T
A
R
T
S
T
A
R
T
1 0 1 0XXX
1 0 1 0 XX X
Device
Select
Device
I²C input/output frame register protocol
Figure 13
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 14
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 Address Read mode can be used if the previous command was issued to the
register where the Read is to take place.
ISO14443B
Select
Code
Code
R/W
ACK
R/W
Input/Output
ACK
Register
Address
shows how to store a PICC request frame command of N Bytes into the
shows how to read an N-Byte PICC answer frame.
Input/Output
01h
Register
Address
01h
ACK
R
E
S
T
A
R
T
1 0 1 0 XXX
ACK
Device
Select
Code
Request Frame
Length N
R/W
N
ACK
Doc ID 8880 Rev 4
Received
Length
ACK
Frame
N
Command
Applying the I²C protocol to the CRX14 registers
Code
PICC
Data 1
ACK
Answer
Data1
Frame
Data
ACK
Command
Parameter
ACK
Data 2
PICC
Answer
Frame
Data 2
Data
ACK
ACK
Command
Parameter
PICC
Answer
Frame
Data
ACK
ACK
Command
Parameter
Data N
Answer
Data N
PICC
Frame
Data
NoACK
ai09243
ai09243
ACK
23/47
S
T
O
P
S
T
O
P