ATA555811-DDT ATMEL [ATMEL Corporation], ATA555811-DDT Datasheet - Page 10

• Manufacturer Part Number: ATA555811-DDT
• Description: 1 kbit R/W IDIC with Deterministic Anticollision
• Manufacturer: ATMEL [ATMEL Corporation]

3.1
Figure 3-1.
3.1.1
10
Data "1"
Data "0"
Data
NRZ
Tag to Interrogator Communication
ATA5558 [Preliminary]
Start of Frame (SOF) Encoding
load off
load on
load off
load on
Tag to Interrogator - Load Modulation Coding
Normal Manchester
data coding
All transmissions from the tag to the interrogator utilize amplitude modulation (ASK) of the RF
carrier. This takes place by controlled switching of a resistive load between the coil pads which in
turn modulates the RF field generated by the interrogator.
The tag is capable of communicating with the interrogator via inductive coupling. Typical exam-
ples of the incorporated amplitude modulation is shown in
After the reception of a valid interrogator command the tag will reply immediately with a Start of
Frame (SOF) pattern. The SOF pattern is made up of a variable length preamble and a fixed
2-bit (Manchester) code violation followed by a half bit duration of unmodulated carrier. The pre-
amble length as set in the configuration block defines the number of (Manchester coded) zero
initialization data bits. If the preamble length in the configuration register is set to zero, a single
start bit will precede on the code violation.
• Manchester encoded data signal
• Bi-phase encoded data signal
• NRZ direct data encoding
• Dual pattern data coding is used during the anticollision loop and for an error code response
T
T
d
d
load on
load on
load off
load off
load on
load off
or
or
Normal Biphase
data coding
T
T
d
d
load off
load on
load off
load on
Figure
Anticollision dual pattern
T
T
3-1:
data coding
d
d
T
T
4681C–RFID–09/05
d
d