DEMOKITCRX14 STMicroelectronics, DEMOKITCRX14 Datasheet - Page 14

• 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
The STOP condition at the end of a Write access
to the Input/Output Frame, Authenticate or Anti-
Collision Register, causes the Radio Frequency
data exchange between the CRX14 and the PICC
to be started.
During the Radio Frequency data exchange, the
CRX14 disconnects itself from the I²C bus. The
time (t
not fixed as it depends on the PICC command for-
mat. To know when the exchange is complete, the
bus master uses an ACK polling sequence as
shown in
Figure 8. CRX14 I²C Write Mode Sequence
14/40
BUS Master
CRX14 WRITE
BUS Slave
RFEX
Figure 9.
) needed to complete the exchange is
It consists of the following:
DEV SEL
R/W
ACK
BYTE ADDR
ACK
DATA 1
ACK
DATA 2
Initial condition: a Radio Frequency data
exchange is in progress.
Step 1: the master issues a START condition
followed by the first Byte of the new instruction
(Device Select Code plus R/W bit).
Step 2: if the CRX14 is busy, no ACK is
returned and the master goes back to Step 1.
If the CRX14 has completed the Radio
Frequency data exchange, it responds with an
ACK, indicating that it is ready to receive the
second part of the next instruction (the first
Byte of this instruction being sent during Step
1).
ACK
DATA 3
ACK
DATA N
ACK
AI09265