u3280m ATMEL Corporation, u3280m Datasheet - Page 5

• Manufacturer Part Number: u3280m
• Description: Transponder Interface For Microcontroller U3280m
• Manufacturer: ATMEL Corporation

3.2.1
3.3
3.4
4688D–RFID–03/07
Field Clock
Gap Detect
Digital Input to Control the Damping Stage (MOD)
MOD = 0: coil not damped
MOD = 1: coil damped
V
Note:
The field clock extractor of the interface makes the field clock available for the microcontroller. It
can be used to supply timer inputs to synchronize modulation and demodulation with the field
clock.
The transponder interface can also receive data. The base station modulates the data with short
gaps in the field. The gap-detection circuit detects these gaps in the magnetic field and outputs
the NGAP/field signal at the NGAP pin. A high level indicates that a field is applied at the coil
and a low level indicates a gap or that the field is off. The microcontroller must demodulate the
incoming data stream at one of its inputs.
V
V
CMS
coil-peak
coil-peak
= V
If the automatic power management is disabled, the internal front-end V
this case the value V
=
=
CID
V
V
: modulation voltage stroke at coil inputs
DD
DD
2
2
+
=
V
V
CMS
CD
DDC
=
V
must be used in the above formula.
CU
DD
is limited at V
U3280M
DDC
. In
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