ATA559001-DDT Atmel, ATA559001-DDT Datasheet - Page 55

• Manufacturer Part Number: ATA559001-DDT
• Description: RF Wireless Misc UHF (1kbit r/w anti-collision)
• Manufacturer: Atmel

8.1.6
8.1.7
8.2
8.2.1
4817C–RFID–03/07
Command Coding
Modulation During the Forward Header
Modulation During the Forward Link
Long Command Codes
ATA5590 changes the state of modulation during the forward header. The modulator is at state0
for a time1 after notch. Time1 is the time the tag needs for internal calculations, and is therefore
also the minimum time for a logical 0.
Note:
Figure 8-3.
Figure 8-3 on page 55
which selects the internal clock frequency. This mechanism has an influence on the backscat-
tered modulation stream if the dynamic coding mechanism is selected (accuracy of the timing).
After becoming synchronous to the link (ATA5590 has received a full command correctly),
ATA5590 backscatters the received data back to the reader.
The modulation coding type is the type which was defined in the previous command. Therefore,
the reader is able to control the link on the fly.
The reset value is Soft NRZI
If a timing reference is needed for encoding, ATA5590 uses the time of 0* as a timing reference.
Commands can control the function of the tag.
After getting the timing definition for PIE out of the forward header section, the tag receives a
6-bit command and 2-bit CRC information. ATA5590 checks the CRC after receiving this 8-bit
frame. If the CRC check passes and the reader does not send an EOT after this section, the tag
interprets the next 8-bit field as a parameter field. An address field, data field, or both can follow
the parameter field (depending on the command and the supported addressing mode which is
stored in the parameter field). At the end, an end of file (EOT) symbol is expected.
Backscatter
Oscillator speed
modulation
The tag operates clock synchronous to an internal oscillator. Therefore, the absolute time is the
difference from bit to bit.
Forward
reader
signal
Modulation During the Forward Header (Tag is Synchronous)
Slow
shows an example of the implemented power management mechanism
Fast
ATA5590
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