sri4k STMicroelectronics, sri4k Datasheet - Page 12

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

Data transfer
3.2.3
Figure 9.
3.3
Figure 10. Example of a complete transmission frame
12/49
Sent by the
Sent by the
Reader
SRI4K
ETU
Answer end of frame
The EOF shown in
Answer end of frame
Transmission frame
Between the Request data transfer and the Answer data transfer, all ASK and BPSK
modulations are suspended for a minimum time of t
to switch from Transmission to Reception mode. It is repeated after each frame. After t
13.56MHz carrier frequency is modulated by the SRI4K at 847kHz for a period of t
to allow the reader to synchronize. After t
forms the start bit (‘0’) of the Answer SOF. After the falling edge of the Answer EOF, the
reader waits a minimum time, t
SOF
at 106kb/s
12 bits
–
–
0
b0
followed by 10 ETUs at logic-0,
followed by 2 ETUs at logic-1.
Cmd
Input data transfer using ASK
10 bits
b1
0
Data
10 bits
t
DR
0
b2
Figure 9
CRC
10 bits
0
b3
CRC
10 bits
is composed of:
2
0
b4
, before sending a new Request Frame to the SRI4K.
EOF
10 bits
0
b5
128/fs
1
t
0
, the first phase transition generated by the SRI4K
0
b6
f s =847.5kHz
128/fs
Sync
t
1
0
b7
Output data transfer using BPSK
0
= 128/ƒ
SOF
12 bits
b8
0
Data CRC CRC
10 bits
S
. This delay allows the reader
0
b9
10 bits
1
b10
10 bits
EOF
t
12 bits
b11
1
2
AI10882
1
SOF
ai07665
= 128/ƒ
SRI4K
0
, the
S