DEMOKITCRX14 STMicroelectronics, DEMOKITCRX14 Datasheet - Page 22

• 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

Applying the I²C protocol to the CRX14 registers
5
5.1
Figure 10. Host-to-CRX14 transfer: I²C write to parameter register
Figure 11. CRX14-to-host transfer: I²C random address read from parameter register
Figure 12. CRX14-to-host transfer: I²C current address read from parameter register
22/47
CRX14 Read
Bus Master
Bus Slave
CRX14 Write
Bus Master
Applying the I²C protocol to the CRX14 registers
I²C parameter register protocol
Figure 10
becomes active after the I²C STOP condition.
Figure 11
sends the Parameter Register contents until it receives a NoACK from the I²C Host.
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.
Bus Slave
S
T
A
R
T
1 0 1 0 X X X
CRX14 Read
Device Select
Bus Master
Bus Slave
shows how new data is written to the Parameter Register. The new value
shows how to read the Parameter Register contents. The CRX14 sends and re-
S
T
A
R
T
Code
1 0 1 0 X X X
Device Select
Code
R/W
S
T
A
R
T
ACK
1 0 1 0 X X X
Parameter Register
Device Select
R/W
Code
ACK
Address
Doc ID 8880 Rev 4
00h
Parameter Register
R/W
Address
ACK
00h
ACK
R
E
S
T
A
R
T
Register Byte
1 0 1 0 X X X
data
Value
ACK
Device Select
Code
Register Byte
NoACK
Value
data
R/W
S
T
O
P
ACK
ACK
Register Byte
S
T
O
P
data
Value
NoACK
ai09242
CRX14
ai09240
ai09241
S
T
O
P