srt512 STMicroelectronics, srt512 Datasheet - Page 9

• Manufacturer Part Number: srt512
• Description: 13.56 Mhz Short-range Contactless Memory Chip With 512-bit Eeprom And Anticollision Functions
• Manufacturer: STMicroelectronics

SRT512
3
3.1
3.1.1
Data transfer
Input data transfer from Reader to SRT512 (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 SRT512’s
antenna is transformed into a Supply Voltage by a regulator, and into data bits by the ASK
demodulator. For the SRT512 to decode correctly the information it receives, the reader
must 10% amplitude-modulate the 13.56 MHz wave before sending it to the SRT512. This is
represented in
Figure 3.
Character transmission format for Request Frame
The SRT512 transmits and receives data bytes as 10-bit characters, with the least
significant bit (b
(Elementary Time 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 ISO14443-3 Type B
Standard. If an error is detected during data transfer, the SRT512 does not execute the
command, but it does not generate an error frame.
Figure 4.
10% ASK MODULATION
OF THE 13.56-MHz WAVE,
GENERATED BY THE READER
DAT A BIT TO TRANSMIT
TO THE
1 ETU
SRT512
10% ASK modulation of the received wave
SRT512 Request Frame character format
Start
"0"
b0
Figure
0
) transmitted first, as shown in
LSb
b1
3. The data transfer rate is 106 Kbits/s.
b2
b3
Information Byte
b4
Transfer time for one data bit is 1/106 kHz
b5
Figure
Figure
b6
4. Each bit duration, an ETU
10. A frame includes an SOF,
b7
MSb
b8
Stop
"1"
b9
Data transfer
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