M24LR64-R_1004 Datasheet, PDF (41/126 Pages) STMicroelectronics – 64 Kbit EEPROM with password protection & dual interface: 400kHz I²C serial bus & ISO 18000-3 mode 1 RF protocol at 13.56MHz

M24LR64-R
9
Data rate and data coding
Data rate and data coding
The data coding implemented in the M24LR64-R uses pulse position modulation. Both data
coding modes that are described in the ISO15693 are supported by the M24LR64-R. The
selection is made by the VCD and indicated to the M24LR64-R within the start of frame
(SOF).
9.1
Data coding mode: 1 out of 256
The value of one single byte is represented by the position of one pause. The position of the
pause on 1 of 256 successive time periods of 18.88 µs (256/f_C), determines the value of the
byte. In this case the transmission of one byte takes 4.833 ms and the resulting data rate is
1.65 Kbits/s (f_C/8192).
Figure 16 illustrates this pulse position modulation technique. In this figure, data E1h (225
decimal) is sent by the VCD to the M24LR64-R.
The pause occurs during the second half of the position of the time period that determines
the value, as shown in Figure 17.
A pause during the first period transmits the data value 00h. A pause during the last period
transmit the data value FFh (255 decimal).
Figure 16. 1 out of 256 coding mode
Pulse
Modulated
Carrier
9.44 µs
18.88 µs
01 2
3 .. . . . . . .
.. . . . . . . .
.. . . . . . . .
2 .....................
2 .....................
5 .....................
2222
5555
2345
4.833 ms
AI06656
Doc ID 15170 Rev 9
41/126