ATA5570-TAQY ATMEL [ATMEL Corporation], ATA5570-TAQY Datasheet - Page 10

• Manufacturer Part Number: ATA5570-TAQY
• Description: Multifunctional 330-bit Read/Write RF Sensor Identification IC
• Manufacturer: ATMEL [ATMEL Corporation]

Figure 5-3.
5.6
5.7
10
Reader-to-tag Communication
Start Gap
Sequence
Sequence terminator not suitable for Biphase or PSK modulation
Waveforms per different modulation types
Manchester
FSK
ATA5570 [Preliminary]
e5550-compatible Sequence Terminator Waveforms
Data is written to the tag by interrupting the RF field with short field gaps (on-off keying) in accor-
dance with the e5550 write method. The time between two gaps encodes the “0” or “1”
information to be transmitted (pulse interval encoding). The duration of the gaps is usually 50 µs
to 150 µs. The time between two gaps is nominally 24 field clocks for a “0” and 54 field clocks for
a “1”. When there is no gap for more than 64 field clocks after a previous gap, the ATA5570 exits
the write mode. The tag starts with the command execution if the correct number of bits were
received. If there is a failure detected the ATA5570 does not continue and will enter regular-read
mode.
The initial gap is referred to as the start gap. This triggers the reader-to-tag communication. Dur-
ing this mode of operation, the receive damping is permanently enabled to ease gap detection.
The start gap may need to be longer than subsequent gaps in order to be detected reliably.
A start gap will be accepted at any time after the mode register has been loaded ( 3 ms). A sin-
gle gap will not change the previously selected page (by former opcode “10” or “11”).
Figure 5-4.
V Coil PP
Bit period
Last bit
Start of Reader-to-tag Communication
Data "1"
Read mode
Modulation
Data "1"
off (on)
Data "1"
S
gap
d
1
Write mode
Modulation
Data "1"
off (on)
W
gap
d
0
bit "1" or "0"
First Bit
4863A–RFID–07/05