DEMOKITCRX14 STMicroelectronics, DEMOKITCRX14 Datasheet - Page 16

• 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
CRX14 I²C Read Operations
To send a Read command, the bus master sends
a START condition, followed by a Device Select
Code and the R/W bit set to ’1’.
The CRX14 that corresponds to the Device Select
Code acknowledges and outputs the first data
Byte of the addressed register.
To select a specific register, a dummy Write com-
mand must first be issued, giving an address Byte
but no data Bytes, as shown in the bottom half of
Figure 10.
stored in the internal address pointer, for use by
the Read command that immediately follows the
dummy Write command.
Figure 10. CRX14 I²C Read Modes Sequences
16/40
I²C CURRENT ADDRESS READ
I²C RANDOM ADDRESS READ
This causes the new address to be
BUS Master
CRX14 READ
BUS Slave
BUS Master
CRX14 READ
BUS Slave
DEV SEL
DEV SEL
R/W
R/W
ACK
ACK
ADDRESS
DATA 1
ACK
ACK
DEV SEL
DATA 2
ACK
In the I²C Read mode, the CRX14 may read one
or more data Bytes depending on the selected reg-
ister. The bus master has to generate an ACK af-
ter each data Byte to read all the register data in a
continuous stream. Only the last data Byte should
not be followed by an ACK. The master then termi-
nates the transfer with a STOP condition, as
shown in
After reading each Byte, the CRX14 waits for the
master to send an ACK during the 9
the master does not return an ACK within this time,
the CRX14 terminates the data transfer and
switches to stand-by mode.
R/W
ACK
DATA 3
DATA 1
ACK
Figure 10.
ACK
DATA 4
DATA 2
ACK
ACK
DATA N
DATA N
NoACK
NoACK
th
bit time. If
AI09266