DEMOKITCRX14 STMicroelectronics, DEMOKITCRX14 Datasheet - Page 17

• 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
4.2
4.3
4.4
The CRX14 continuously monitors the SDA and SCL lines for a START condition (except
during Radio Frequency data exchanges), and will not respond unless one is sent.
I²C stop condition
STOP is identified by a Low-to-High transition of the Serial Data line, SDA, while the Serial
Clock, SCL, is stable in the High state.
A STOP condition terminates communications between the CRX14 and the bus master.
A STOP condition at the end of an I²C Read command, after (and only after) a NoACK,
forces the CRX14 into its stand-by state.
A STOP condition at the end of an I²C Write command triggers the Radio Frequency data
exchange between the CRX14 and the PICC.
I²C acknowledge bit (ACK)
An acknowledge bit is used to indicate a successful data transfer on the I²C bus.
The bus transmitter, either master or slave, releases the Serial Data line, SDA, after sending
8 bits of data. During the 9th clock pulse the receiver pulls the SDA line Low to acknowledge
the receipt of the 8 data bits.
I²C data input
During data input, the CRX14 samples the SDA bus signal on the rising edge of the Serial
Clock, SCL. For correct device operation, the SDA signal must be stable during the Low-to-
High Serial Clock transition, and the data must change only when the SCL line is Low.
Doc ID 8880 Rev 4
CRX14 I²C protocol description
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