sri4k STMicroelectronics, sri4k Datasheet - Page 9

• Manufacturer Part Number: sri4k
• Description: 13.56 Mhz Short-range Contactless Memory Chip With 4096-bit Eeprom And Anticollision Functions
• Manufacturer: STMicroelectronics

SRI4K
3
3.1
3.1.1
Data transfer
Input Data Transfer from the Reader to the SRI4K (Request
Frame)
The reader must generate a 13.56 MHz sinusoidal carrier frequency at its antenna, with
enough energy to “remote-power” the memory. The energy received at the SRI4K’s antenna
is transformed into a Supply Voltage by a regulator, and into data bits by the ASK
demodulator. For the SRI4K to decode correctly the information it receives, the reader must
10% amplitude-modulate the 13.56 MHz wave before sending it to the SRI4K. This is
represented in
Figure 3.
Character Transmission Format for Request Frame
The SRI4K transmits and receives data bytes as 10-bit characters, with the least significant
bit (b
Unit), is equal to 9.44 µs (1/106 kHz).
These characters, framed by a Start Of Frame (SOF) and an End Of Frame (EOF), are put
together to form a Command Frame as shown in
commands, addresses, data, a CRC and an EOF as defined in the ISO 14443-3 Type B
Standard. If an error is detected during data transfer, the SRI4K does not execute the
command, but it does not generate an error frame.
Figure 4.
10% ASK MODULATION
OF THE 13.56MHz WAVE,
GENERATED BY THE READER
DATA BIT TO TRANSMIT
TO THE
1 ETU
0
) transmitted first, as shown in
SRI4K
Start
"0"
b0
10% ASK modulation of the received wave
SRI4K request frame character format
Figure
LSb
b1
3. The data transfer rate is 106 Kbits/s.
b2
b3
Information Byte
b4
Figure
Transfer time for one data bit is 1/106 kHz
b5
4. Each bit duration, an ETU (Elementary Time
b6
Figure
b7
10. A frame includes an SOF,
MSb
b8
Stop
"1"
b9
Data transfer
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