sri512 STMicroelectronics, sri512 Datasheet - Page 9
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sri512
Manufacturer Part Number
sri512
Description
13.56-mhz Short-range Contactless Memory Chip With 512-bit Eeprom And Anti-collision Functions
Manufacturer
STMicroelectronics
Datasheet
1.SRI512.pdf
(50 pages)
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3.1
3.1.1
Data transfer
Input data transfer from the Reader to the SRI512 (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 SRI512’s
antenna is transformed into a Supply Voltage by a regulator, and into data bits by the ASK
demodulator. For the SRI512 to decode correctly the information it receives, the reader must
10% amplitude-modulate the 13.56 MHz wave before sending it to the SRI512. This is
represented in
Figure 3.
Character transmission format for Request Frame
The SRI512 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 SRI512 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
DAT A BIT TO TRANSMIT
TO THE
0
) transmitted first, as shown in
1 ETU
SRI512
10% ASK modulation of the received wave
SRI512 Request Frame character format
Start
"0"
b0
Figure
LSb
b1
3. The data transfer rate is 106 Kbits/s.
b2
b3
Figure
Information Byte
b4
Transfer time for one data bit is 1/106 kHz
4. Each bit duration, an ETU (Elementary Time
b5
Figure
b6
10. A frame includes an SOF,
b7
MSb
b8
Stop
"1"
b9
Data transfer
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