Operation Manual

Application Note
DN[Document ID]
AS3911
General Purpose Demo V3.0
ams Application Note
[v1-02] 2015-Sep-07
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Content Guide
1
General Description ............................................................................................................. 4
2
Hardware .............................................................................................................................. 4
2.1
Overview .............................................................................................................................. 4
2.1.1
PCB power supply................................................................................................................ 5
2.1.2
Microcontroller ...................................................................................................................... 6
2.1.3
AS3911 ................................................................................................................................ 7
2.1.3.1
Power supply system ........................................................................................................... 7
2.1.3.2
Capacitive wake up .............................................................................................................. 8
2.1.3.3
Filter and matching network ................................................................................................. 8
3
Antenna and capacitive electrodes .................................................................................... 10
3.1
PCD antenna ...................................................................................................................... 10
3.2
Capacitive electrodes ......................................................................................................... 11
4
Simulation .......................................................................................................................... 12
4.1
Models ................................................................................................................................ 12
4.2
Results ............................................................................................................................... 13
5
Measurements ................................................................................................................... 15
5.1
Antenna parameters........................................................................................................... 15
5.2
Target matching impedance & Q – factor .......................................................................... 15
5.3
Current consumption .......................................................................................................... 16
5.4
Wave shapes, ISO / IEC 14443 ......................................................................................... 16
5.5
ISO / IEC compliance ......................................................................................................... 21
5.5.1
ISO / IEC 14443 ................................................................................................................. 21
5.5.1.1
Class 1 ............................................................................................................................... 21
5.6
EMC ................................................................................................................................... 23
6
Layout recommendations regarding EMC ......................................................................... 24
6.1
Layer stack up .................................................................................................................... 24
6.2
Routing ............................................................................................................................... 25
6.3
Component placement ....................................................................................................... 26
7
Software ............................................................................................................................. 27
7.1
Main features ..................................................................................................................... 27
7.2
Getting started .................................................................................................................... 27
7.2.1
Demo board installation ..................................................................................................... 27
7.2.2
GUI installation ................................................................................................................... 27
7.3
Graphical user interface (GUI) ........................................................................................... 28
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7.3.1
Startup tab .......................................................................................................................... 28
7.3.2
Settings tab ........................................................................................................................ 28
7.3.3
Multi Transponders tab ...................................................................................................... 29
7.3.4
ISO 14443A tab.................................................................................................................. 30
7.3.5
ISO 14443B tab.................................................................................................................. 31
7.3.6
ISO 15693 tab .................................................................................................................... 32
7.3.7
FeliCa tab ........................................................................................................................... 33
7.3.8
NFCIP tab .......................................................................................................................... 34
7.3.9
Antenna features tab .......................................................................................................... 35
7.3.10
Wakeup tab ........................................................................................................................ 36
7.3.10.1 Capacitive Wakeup ............................................................................................................ 36
7.3.10.2 Inductive wakeup ............................................................................................................... 37
7.3.11
Debug tab ........................................................................................................................... 39
7.3.12
Topaz tab ........................................................................................................................... 40
7.3.13
NFC type 2 tab ................................................................................................................... 41
7.3.14
AS3953 tab ........................................................................................................................ 42
7.3.14.1 File transfer tab .................................................................................................................. 43
7.3.14.2 EEPROM ............................................................................................................................ 44
7.3.14.3 E-Paper Reference Design ................................................................................................ 44
7.3.15
SL13A tab .......................................................................................................................... 45
7.3.16
Firmware update ................................................................................................................ 47
8
References ......................................................................................................................... 48
9
Ordering & Contact Information ......................................................................................... 49
10
Copyrights & Disclaimer ..................................................................................................... 50
11
Revision Information .......................................................................................................... 51
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1
General Description
This application note describes the hardware, software and features of the AS3911 General
Purpose V3.0 demo board.
Further simulation and measurements results and layout design recommendations regarding EMC
are introduced.
2
2.1
Hardware
Overview
The demo board is powered and controlled via USB. Figure 1 shows the block diagram of the
board.
It can be separated into four main sections:
1. PCB power supply:
An LDO supplies the micro controller with 3V3 and the AS3911 IC
can be supplied with 3V3 or 5V.
2. Microcontroller:
The PIC24FJ64GB002 controls the AS3911 via SPI
3. HF reader IC AS3911:
This section consists of three sub – sections:
a. Power supply system: Decoupling capacitors of the internal regulators are placed
next to the chip.
b. Capacitive wake up: The CSI / CSO pins are used for the capacitive wake up
feature.
c.
Filter and matching network: This sub – section converts the rectangular output
signal of the IC push pull driver into a sine shape one and converts the AS3911
output impedance to the antenna impedance.
Furthermore the matching network consists of the tuning capacitor bank for the
AAT (Automatic Antenna Tuning) and the Feedback loop (RX line) with the
capacitive voltage divider.
4. Antenna and capacitive wake up electrodes: The antenna, which is coupled to the matching
network generates the magnetic field strength and the electrodes are used to measure the
capacitive differences.
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Figure 1: Block diagram of the demo board
3V3
5V
LDO
3V3
USB
Connector
Micro
controller
USB
SPI
2,4 – 5,5V
Tuning capacitor
bank
EMC filter
Matching Feedback
NW
loop
Antenna
coil
AS3911
Decoupling caps of
internal regulators:
AGD,VSP_D,
VSP_A, VSP_RF
Quartz crystal
oscillator
EMC filter network
Matching network
Uchi p
UA
U2
Schematic level
2.1.1 PCB power supply
Figure 2: PCB power supply schematic
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
Ferrite beads (L1, L2) and decoupling capacitors (C6, C18, and C50) are placed between
USB connector and power/GND plane of the demo board in order to reject unwanted
emissions of the AS3911 HF driver stages. If these emissions would not be damped, the
USB cable would act as an antenna and radiate out the unwanted emissions.

ESD suppressors D2, D3, D5 are used to protect the USB power and the data connections.

The Zener diode D4 protects the input of the voltage regulator.

This section also contains an LDO to convert the 5V USB voltage to 3V3.

LED D1 is used to indicate the USB power connection.
2.1.2 Microcontroller
Figure 3: Microcontroller schematic

The microcontroller is a PIC24FJ64GB002 with internal USB.

The connector P1 is used for programming the microcontroller.

The switch S1 allows the AS3911 to operate with 5V or 3V3.

The diodes D6 (Receive) and D7 (Transmit) indicate the input and output signals of the
RFID communication.

The connector P5 is a solder bridge. It is possible to drive an external AS3911 board with
the microcontroller and the Demo GUI of this demo board or vice versa.

The remaining capacitors and resistors are placed according the PIC24FJ64GB004 Family
datasheet (chapter 2.0).
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2.1.3 AS3911
2.1.3.1
Power supply system
Figure 4 shows the schematic of the AS3911 power supply system.
The internal LDO needs to be decoupled with two capacitors in parallel. These pins are:

AGD (analog ground)

VSP_D (to supply the digital part)

VSP_A (to supply the analog part)

VSP_RF (to supply the driver stage)
The AS3911 contains an internal level shifter that enables the connection to a microcontroller with
different VDD. But Pin 1 should be connected to the same voltage as the supply of the
microcontroller.
The ferrite bead L4 is mounted in the supply line V_RF to reject unwanted emissions of the HF
driver stages.
Jumper J3 can be used to measure the current consumption of the HF reader IC.
The decoupling caps of the VDD and the VDD_IO line are also used to reject unwanted emissions
of the HF driver stages.
Figure 4: Power supply system & capacitive wake up schematic
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Figure 5: Filter and matching network
2.1.3.2
Capacitive wake up
Figure 4 also shows the schematic of the capacitive wake up function.
The CSI / CSO pins of the reader IC are connected to the capacitive electrodes, which are needed
for the capacitive difference measurements and further for the capacitive wake up feature.
Details about this feature can be found in the application note:” AS3911 AN Wakeup modes 2V0”.
This application note is available on request from ams sales representatives at
www.ams.com/Contact-Us/Sales-Offices.
Ultra Small Surface Mount Coaxial Connectors (U.FL Series) are also mounted on the CSI / CSO
line in order to connect external wake up electrodes.
2.1.3.3
Filter and matching network
Figure 5 shows the schematic of the filter and matching network, the return path to the receiver, the
tuning capacitor bank and the antenna connection.
The AS3911 is driven with a differential output. There is the option to drive the Reader IC single –
ended, too. This is described in detail in the application note: “AS3911 AN 50 Ohm single ended
V2”. This application note is available on request from ams sales representatives at
www.ams.com/Contact-Us/Sales-Offices.
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
2-pin connector J5: It is placed between the IC output and the EMC-filter in order to
measure the designed target impedance of the whole network.

EMC filter: It consists of the components: R23/25, L5/6 & C33/34. The resistor is needed to
reach a higher ohmic area for the AAT. R23/25 define basically the impedance operation
point of reader matching with AAT. Suitable inductors with lower Q could also be used.
The inductors were chosen regarding self-resonance frequency, Q – factor, rated current,
filter cut off frequency and target impedance behavior.
The capacitors were chosen regarding filter cut off frequency and target impedance
behavior.
Detailed information about the EMC filter design can be found in the application
note:”AS3911 AN Antenna Design Guide V1.4”. This application note is available on
request from ams sales representatives at www.ams.com/Contact-Us/Sales-Offices.

Matching network: It consists of the capacitors C30 to C32.
The rated voltage of C31 should be higher than the differential antenna voltage!
More detailed information can be found in the application note:”AS3911 AN Antenna Design
Guide V1.4”. This application note is available on request from ams sales representatives at
www.ams.com/Contact-Us/Sales-Offices.

Return path (RX line): It consists of the capacitive voltage divider (C35 to C38), which
brings the input voltage to around 2.5Vpp.
Further 1-pin connectors (P7 & P8) are places in the two return lines to be able to measure
the input voltage.

Tuning capacitor bank: The capacitors C22, C23, C25 & C27 belong to the line Trim1 and
RFO1. C24, C26, C28 & C29 belong to the line Trim 2 and RFO2.
The not placed capacitors C39 to C46 are for a possible voltage divider option, if the
antenna differential voltage exceeds 40Vpp.

Antenna connection: This 3-pin connector enables the connection of external antennas. In
this case R14 & R19 have to be removed.
The not placed R24 can be used for electrical compensation of the antenna. This helps to
reduce unwanted emissions in combination with the possible voltage divider option (adding
C39 to C46)
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3
Antenna and capacitive electrodes
3.1
PCD antenna
A symmetrical 2 – turn coil antenna was chosen (see Figure 6).
Dimensions:

Length:
105.9 mm

Width:
52.6 mm

Trace width:
0.762 mm

Gap width:
0.51 mm
Figure 6: PCD antenna (top layer) and capacitive electrodes (bottom layer)
The electrical antenna parameter can be found in chapter 5.1.
There is the option for electrical compensation of this antenna by mounting R 24. Details can be
found in chapter 2.1.3.3.
The antenna covers the outer edge of the PCB in order to have the biggest area and to be as far as
possible away from the electrical circuits and capacitive electrodes.
The antenna is larger than a Class 1 PICC to reduce the coupling between PCD and PICC antenna.
The corners of the antenna are rounded to reduce the inner resistance and to obtain a more
homogeneous magnetic field radiation. Be aware, that a round or a quadratic antenna would have
the most homogeneous magnetic field radiation.
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3.2
Capacitive electrodes
Figure 6 shows these electrodes and its dimensions, too. They are needed to measure the
capacitive differences between the CSI / CSO pins. Details can be found in chapter 2.1.3.2
A guide line and simulations regarding the electrode dimensions can be found in the application
note “AS3911 AN Wakeup Electrodes V1”. This application note is available on request from ams
sales representatives at www.ams.com/Contact-Us/Sales-Offices.
Basically the bigger the electrodes and the electrode distance is, the higher the capacitive
difference and the detection range.
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4
Simulation
QUCS (Quite universal circuit simulator) is used for designing the filter and matching network.
Detailed information about this software tool and the used models can be found in the application
note: “AS3911 AN Antenna Design Guide V1.3”
4.1
Models
Figure 7: S- Parameter model
Figure 8: Transient & AC model
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4.2
Results
Figure 9 shows the results of the reflection factor S11, the transmission factor S21, the target
matching impedance in the Smith chart and the system Q – factor.
Only the antenna resonance can be seen in this view, because the simulation bandwidth was
limited to 12 MHz but the EMC filter resonance frequency is around 11 MHz.
Further the target matching impedance is calculated with 11.56-j2.02Ω and the system Q – factor
results in 14.4.
Figure 9: S – parameter simulation results
Figure 10 shows in the transient simulation the wave shape of the output signal (red) in comparison
to the rectangular output voltage of the driver. There should be no significant overshoot, which is
realized here.
The blue curves show the input voltage after the capacitive voltage divider. This voltage should not
exceed 2.5 Vpp. The results here show more than 3 Vpp, because of the certain inaccuracy of the
simulation.
The phase difference diagram of the AC simulation results is the most important one. It gives a
good indication, whether the phase difference is in a range where it is measurable (±30° to 150°).
This is also realized here (-100°).
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Figure 10: Transient & AC simulation results
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5
Measurements
Most of the measurements are described in the application note: “AS3911 AN Antenna Design
Guide V1.4”. All others are described in this document. This application note is available on request
from ams sales representatives at www.ams.com/Contact-Us/Sales-Offices.
5.1
Antenna parameters
Figure 11: Measured antenna parameters
Equivalent circuit
L
990 nH
Rs,dc
600 mOhm
fwork
13,56 MHz
fres
69 MHz
Rp@fres
20 kOhm
Cpar
5,37 pF
K
2,26
Rp@fwork
45,12 kOhm
Rp,dc
11,86 kOhm
Rp,tot
9,39 kOhm
Qb
111
Measured inductivity@1 MHz
Measured serial DC resistance@1 MHz
Working frequency
Measured self-resonance frequency
Measured parallel resitor caused by the Skin effect@fres
Parasitic capacitance
Correctur value for Skin effect
Parallel resitor caused by the Skin effect@fwork
Parallel resistor calculated out of the serial DC resistance@1 MHz
Total parallel resistor (Rp//Rpdc)
Basic Quality- factor of the antenna
L
Rp@fres
Cpar
Rp@fres
Cpar
Rp,dc
Rp,tot
L
Cpar
L
Rs,dc
The three parameters for the parallel equivalent circuit are:

L=
990 nH

Cpar=
5.4 pF

Rp, tot=
9.39 kΩ
These values were used for the simulations.
5.2
Target matching impedance & Q – factor
Figure 12 shows the measurement results. The matching impedance is around 14.9+j2.6Ω. The Q
is around 11.5. Both values fit well in terms of current consumption, different data rates and wave
shapes. The EMC filter resonance frequency is around 10.5 MHz.
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Figure 12: Target matching impedance & Q – factor
5.3
Current consumption
The power consumption is measured in CW mode, the antenna was calibrated to a trim value of
eight, the operation voltage is adjusted to 4.5V and the Jumper J3 is used to connect the
Multimeter.
Table 1: Current consumption
Working condition (register settings)
Current consumption [mA]
0x2: en=1, rx_en=1, tx_en=1
184
The measurement was performed without card close to the PCD antenna.
If there is a card close to the PCD antenna, the current consumption will decrease to around 100
mA.
5.4
Wave shapes, ISO / IEC 14443
The measurements were carried out unloaded with a calibration coil.
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Figure 13: Type A, 106 kbps
Figure 14: Type A, 212 kbps
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Figure 15: Type A, 424 kbps
Figure 16: Type A, 848 kbps
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Figure 17: Type B, 106 kbps
Figure 18: Type B, 212kbps
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Figure 19: Type B, 424 kbps
Figure 20: Type B, 848 kbps
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5.5
ISO / IEC compliance
These compliance tests were done with commercial available setups made by Micropross.
5.5.1 ISO / IEC 14443
5.5.1.1
Class 1
Figure 21: Result overview of the ISO 14443 Class 1 tests
Name
Description
Result
1
Alternating
magnetic field
PASSED
2
Procedure for
Hmax
Procedure for
Hmin
This test determines that the PCD generates a field not higher than
the average value specified in ISO/IEC 14443-1:2010, in any possible
position.
This test determines that the DUT with its specified antenna
generates a field not higher than the value Hmax
This test determines that the DUT is able to supply a field strength of
at least Hmin to power the reference device placed anywhere within
the defined operating volume
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
This test determines the modulation index of the PCD field as well as
the rise and fall times and the overshoot values as defined in ISO/IEC
14443-2 within the defined operating volume.
The purpose of this setting is to find the limit of understanding of the
PCD under test.
The purpose of this measurement is to measure the PCD load
modulation sensitivity for the tested positions
3
4
Type A
5
Type B
6
Type A at 106
kbps
7
Type A at 212
kbps
8
Type A at 424
kbps
9
Type A at 848
kbps
10
Type B at 106
kbps
11
Type B at 212
kbps
12
Type B at 424
kbps
13
Type B at 848
kbps
14
Setting
15
Measurement
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PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
PASSED
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Name
Description
Result
16
Setting
PASSED
17
Measurement
The purpose of this setting is to find the limit of understanding of the
PCD under test.
The purpose of this measurement is to measure the PCD load
modulation sensitivity for the tested positions
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PASSED
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5.6
EMC
FCC Title 47 Part 15, Class B pre - scans were done to evaluate the EMC of the demo board.
The demo board conditions (GUI adjustment) are as follows:
1. Battery pack - power supply (4 x 1.2V, AA) is connected between USB connector and ferrite
beads L1 & L2 (see Figure 2)
2. “Demo Board Check” button pressed
3. “Calibrate Antenna” button pressed (trim value: 8)
4. Adjust regulator button pressed
5. Repeat steps 3 & 4 to make sure that the voltage level is adjusted correctly
Figure 22 shows that the highest unwanted emissions of the demo board are at the 3rd harmonics of
the 13.56 MHz (40.68 MHz) and several frequencies between 200 and 500 MHz.
All emissions are clearly under the FCC spectrum mask.
This measurement was done without a transponder in the reader field.
Figure 22: FCC Title 47 Part 15, Class B pre - scan
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6
Layout recommendations regarding EMC
This chapter describes the countermeasures against unwanted emissions on the General Purpose
Demo Board V3. More detailed information about this topic can be found in the application note:
“AN PCB layout recommendation”.
6.1
Layer stack up
At least a 4 – layer stack is recommended for an AS3911 PCB in terms of EMC performance.
The 4 – layer of the General Purpose Demo Board V3 demo are:

Top layer (Signal)

GND plane (GND)

Power plane (VBUS)

Bottom layer (Signal)
The detailed stack can be found in Figure 23. A 4 – layer design was chosen to have a good
compromise between costs and EMC performance.
Figure 23: GP V3, PCB layer stack
Remark:
The GND - & power plane were designed to get a low-impedance GND/power – system. They are
the inner layers, because this system can be shielded by the outer signal layers. Furthermore the
distance between the GND and the power plane should be reduced to a minimum (50µm) to
increase the capacitance between the planes. This increased capacitance supports the recharging
process of the GND/power – system to avoid a too strong jitter of the supply voltage.
The GND/power plane combination acts as a waveguide. Therefore a fence of vias (GND & signals)
was installed to avoid the emission radiation out of the plane edges.
Figure 24 shows the realization on the demo board.
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Figure 24: Via - fence on the plane edges
6.2
Routing

Fast switching signal traces should be as short as possible.

Current return paths should be as short as possible.

GND plane should not be slotted.

Dead copper should be grounded.

Component GND pads and vias are directly connected to GND to achieve the shortest
possible current paths.

Power plane:
This demo board has four sub – planes (see Figure 25):
o
VBUS
o
3.3V
o
V_RF
o
VSP_RF
Figure 25: The four sub – planes of the power plane
VBUS

3,3V
V_RF
VSP_RF
The differential filter – and matching network should be designed symmetrical.
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6.3
Component placement

Placing the decoupling capacitors as close to the IC´s as possible (small loop areas, small
inductance).

Component GND pads should be as close to the IC as possible (short current return paths)

Clear arrangement between digital and analog areas.

The component placement of the USB power connection is shown in Figure 26.
Figure 26: USB power connection to the power plane
EMC measurement results like in chapter 5.6 can be achieved with all these design rules.
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7
Software
7.1
Main features

7.2
Supported protocols:
o
ISO 14443
o
ISO 15693
o
Felica
o
NFC Type 2
o
ISO 18092 (NFCIP-1) Active P2P
o
Topaz
o
iCLASS
o
Kovio

Automatic Antenna tuning (AAT)

Wake up (capacitive & inductive)

Multi transponder detection

Easy access to the register map
Getting started
7.2.1 Demo board installation
Plug in the reader on a USB port. For AS3911 general purpose board you need a USB Port that can
provide >200 mA since the AS3911 is using USB power. Usually those ports are direct on the PC or
use the Laptop or on a powered Hub.
7.2.2 GUI installation
Follow the GUI install procedure by running application file: AS3911GUIv2_2-3-0-0.exe.
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7.3
Graphical user interface (GUI)
7.3.1 Startup tab
When the GUI is started, the window in Figure 27 appears. The indicator on the right bottom corner
shows the connection status. If the board is successfully connected via USB, then the status turns
to green and displays the version of the firmware.
Click of the button “Demo Board Check” read status information of the Demo board and checks
whether a firmware update is needed. The configuration of the AS3911 is done based on this
information.
Figure 27: Startup window
The next step is to press the “Calibrate Antenna” button to tune the antenna to 13.56 MHz.
Afterwards the “Adjust Regulators” button has to be pressed in order set the internal regulators to
improve system Power Supply Rejection Ratio (PSRR).
Remark:
The “Adjust Regulators” button has to be pressed always after the “Calibrate Antenna” button to
obtain the real power consumption of the AS3911 during operation.
7.3.2 Settings tab
Figure 28 shows the Settings window. Some important register settings can be modified here.
Furthermore it is possible to read out the current settings, load and save them.
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Figure 28: Settings window
7.3.3 Multi Transponders tab
This tab shows the anti-collision and multi-protocol feature of AS3911 board (see Figure 29)
On opening, all standards are active and by press the “Find” button, the reader start to scan for tags
that are in the proximity of the reader. Press the “Find” button during the interrogation process to
stop the interrogation process.
The log screen shows the UIDs or PUPIs, the type and how often the transponder is scanned. The
time stamp shows the last scan.
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Figure 29: Multi Transponder window
Additional the following protocols are supported:

Kovio Barcode 128/256 bit (ISO 14443A checkbox)

iCLASS (ISO 15693 checkbox)
7.3.4 ISO 14443A tab
In this tab the IS014443A operation of the AS3911 is demonstrated. Figure 30 shows the ISO
14443-A window of the GUI.
After clicking the button “Configuration”, an IS014443A transponder can be placed into the reader
field. The button “REQA ->Active” or “WUPA ->Active” starts the anti-collision procedure and the
UID number of the transponder is displayed.
If the card/tag supports ISO 14443-4, further commands like RATS or PPS can be carried out.
After RATS or PPS – button was pressed, APDU frames can be sent by using “Debug” tab (see
chapter 7.3.11)
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Figure 30: ISO 14443A window
7.3.5 ISO 14443B tab
In this tab the IS014443A operation of the AS3911 is demonstrated. Figure 31 shows the ISO
14443-B window of the GUI.
The command “configuration” prepares the board for ISO 14443-B communication and start the
sequence to set the modulation depth. The sequence activates the transmission, measures the
modulation depth and adapts it to comply with the modulation depth specified in the box
“Modulation Index”. See AS3911 Datasheet, section AM modulation depth definition using direct
command calibrate modulation depth.
After clicking the button “Configuration”, an ISO14443-B transponder can be placed in the reader
filed. Clicking button “REQB” or “WUPB” starts the interrogation procedure and the “PUPI” number
of the transponder is displayed.
If the card/tag supports ISO 14443-4, further commands like ATTRIB can be carried out.
After ATTRIB – button was pressed, APDU frames can be sent by using “Debug” tab (see chapter
7.3.11)
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Figure 31: ISO 14443B window
7.3.6 ISO 15693 tab
In this tab the IS0 15693 operation of the AS3911 is demonstrated. Figure 32 shows the ISO 15693
window of the GUI.
The command “Configuration” prepares the board for ISO 15693 communication. This configuration
starts a firmware sequence to set the modulation depth as described in chapter 7.3.5 (ISO14443
Type B).
It sets as well ISO 15693 parameter for the receive data rate and the number of slots that are used
in the anti-collision round in the firmware.
The button “Inventory” start the interrogation and scan for the Vicinity Integrated Circuit Card
(VICC).
After end of the Interrogation process, a Tag can be picked by UID and the “Get System
Information” can be issued which will request the VICC for supported features.
The command “Read blocks” will read out and display the memory blocks of the VICC.
Remark:
Not all vicinity cards support “Get System Information” command.
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Figure 32: ISO 15693 window
7.3.7 FeliCa tab
In this tab the FeliCa functionality of the AS3911 is demonstrated. Figure 33 shows the FeliCa
window of the GUI.
The command “Configuration” prepares the board for FeliCa communication. This configuration
starts a firmware sequence to set the modulation depth as described in chapter 7.3.5 (ISO14443
Type B).
The number of slots that are used in the anti-collision round in the firmware can also be set.
The button “Poll” starts the interrogation and scans for FeliCa transponder.
FeliCa Lite features can be shown with the default content of the “Felica Card Commands View”
group box.
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Figure 33: Felica window
7.3.8 NFCIP tab
In this tab the active peer – to peer functionality of the AS3911 is demonstrated. Figure 34 shows
the NFCIP window of the GUI.
Please note that this feature requires a NFC enabled smart phone or tablet.
The AS3911 is initially configured to cycle through the initiator and target mode. The default setting
for the bitrate is 424kbps. The communication starts automatically, when tab is selected.
Once the link is established, the initial grey phone picture on the GUI is replaced by a colored one.
It is possible to transfer an URL to the phone by using the established connection.
The command “=URL =>” starts the transfer and the browser in the phone will open the requested
URL.
Furthermore it is possible to transfer pictures to the phone. Three sample pictures are provided by
the GUI and a further option “Image from Disk” provides an individual option to select a file. After a
click on one picture the transfer is started. Please note that the transfer of the picture takes several
seconds since it contains a large amount of data. Please wait till the picture is transferred. You
should not interrupt the transfer.
The phone will display the received picture with the comment “new Tag received”.
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Figure 34: NFCIP window
7.3.9 Antenna features tab
The automatic antenna tuning feature of the AS3911 is demonstrated in this tab. Figure 35
shows Antenna feature window of the GUI.
The antenna resonates at 13,56MHz, if the pointer shows maximum input signal amplitude. A target
phase can be chosen to use it as a reference for the internal algorithm.
After activating the command “Measure Antenna” the amplitude of the input signals and the phase
differences between output and input signal is measured and displayed on the graph and the
command line on the bottom.
Input amplitude and phase difference can be continuously monitored by using the command
“Continuous Measurement”. Once this option is activated, a detuning effect can be seen while
approaching a piece of metal to the antenna.
The antenna can be tuned by the button “Auto Adjust Antenna”. This can be done continuously by
using the button “Continues Adjust Antenna”.
It is possible to manually adjust the trim value with the List Box “Trimming values”. It is
recommended to use the “Continues Measurement” for this investigation. Note that the value of -1
will not change the settings.
The antenna feature tab can be easily used for matching network evaluation of other AS3911-based
readers. Chapter 2.1.2 describes the realization of an SPI - connection between the µC of the GP
V3.0 and an AS3911 on an external reader board.
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Figure 35: Antenna Feature (Automatic Antenna Tuning) window
7.3.10 Wakeup tab
The wakeup Tab is designed to demonstrate the low power wakeup modes of AS3911 (capacitive
or inductive wakeup). The AS3911 offers three wake up modes that generate an interrupt to the
microcontroller in deep sleep.
Remark:
Since this demonstrator is for evaluation purposes, there are continuous measurements update
enabled which result in extra current consumption. To avoid interaction with the AS3911 during the
deep sleep mode, the user can avoid that update and minimize the current consumption by enable
the "read at interrupt only" switch.
7.3.10.1
Capacitive Wakeup
Figure 36 shows the wakeup window with the capacitive wakeup enabled.
This method observes the capacitance across two electrodes. Since parasitic capacitances
influence need to be rejected for that measurement, a calibration needs to be done first.
This calibration is easily done by activating the “AutoCalibrate” button. Alternatively, it is possible to
manually set the calibration value.
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Remark:
The “AutoCalibrate” button only works in the auto-position.
Before the scan is started, the initial status (Offset) of the system needs to be set. That step is
executed by clicking on the “Measure” button and “Measurement to Offset” button.
The wakeup detection starts with the “Start” button, the actual measurement values are shown in
Figure 36. An interrupt is indicated by a red dot.
Figure 36: Wakeup window – Capacitive wake up enabled
The additional parameters define the window in which no interrupt is generated (Delta window size).
In case the actual measured value is within the window range, no interrupt will be generated.
The Timer period defines how often the measurement procedure is executed.
The selection box “Automatic averaging” selects an automatic or static offset value. In case of an
auto averaging, the offset is dynamically adjusted to the environment condition. If this option is
active, the offset changes dynamically with a weighted factor which can be selected. The weight
option defines how fast the offset value is being adapted to the new environment condition.
7.3.10.2
Inductive wakeup
The inductive wakeup scans periodically the input signal amplitude and the phase difference of the
output and input signal. If there is change of one of these two antenna tuning parameters, an
interrupt is generated.
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Remark:
The antenna needs to be tuned before starting the inductive wakeup procedure.
Figure 37 shows the wakeup window with the phase differences measurement.
The same procedure is used to obtain the offset level than for the capacitive wakeup in chapter
7.3.10.1.
Figure 37: Wakeup window – Inductive (phase) wake up enabled
The wakeup window with the input signal amplitude measurement is shown in Figure 38.
Remark:
Different wakeup ranges can be achieved with the phase or amplitude method. This depends
basically on the antenna matching network.
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Figure 38: Wakeup window – Inductive (amplitude) wake up enabled
7.3.11 Debug tab
The debug is split into two group boxes:

“Send Direct Command” allows sending AS3911 direct commands. Please note that it only
makes sense to play around with these commands when you have read and understood
the AS3911 data sheet.

“TxRxNBytes” allows sending of arbitrary hex-encoded byte strings with the previously
selected protocol directly through the FIFO. Please note that this is not possible for
ISO15693 since there the firmware has to do the bit coding.
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Figure 39: Debug window
7.3.12 Topaz tab
This tab shows the Topaz (Type 1Tag) functionality. Pressing “Configuration” sets the reader in CW
(continuous wave) mode.
After pressing the “Select” button (sending a WUPA) the UID of the Type 1 Tag is shown and
reading and writing in the memory blocks is possible.
The Topaz window of the GUI is shown in Figure 40.
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Figure 40: Topaz window
7.3.13 NFC type 2 tab
The NFC type 2 tag application is demonstrated in this tab. Figure 41 shows the GUI window.
The reader has to be set with the button “Configuration”, because this is a 14443-A application.
The interrogation for cards will be started with the command “WUPA->Active”.
Reading of the card memory content is initiated with the command “Execute” while the radio button
“READ Data from Page” is active.
Writing to the memory is initiated with the command “Execute” while the radio button “WRITE Data
from Page” is active.
Locking a page can be initiated with the command “Execute” while the “LOCK Page” is active.
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Figure 41: NFC Type 2 window
7.3.14 AS3953 tab
The AS3953 tab allows to perform some demonstrations with the AS3953 NFC Interface demo tag.
Remark:
An AS3953 demo kit has to be placed in the reader field, it has to be connected to a PC and the
AS3953 GUI should be opened.
This tab consists of four sub – tabs:

File transfer

EEPROM

E- Paper Reference Design
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7.3.14.1
File transfer tab
Figure 42 shows the File transfer window.
To transmit from AS3911 (Reader) to AS3953 (NFiC):
On AS3911 GUI select “load image”, select “speed settings” and click on “Write to Card”
to execute the file transfer.
To transmit from AS3953 (NFiC) to AS3911 (Reader):
On AS3953 GUI select “load Image”. On AS3911 GUI, select “speed settings” and click
on “Read from Card” to execute the file transfer.
Figure 42: AS3953 File transfer window
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7.3.14.2
EEPROM
Figure 43 shows the EEPROM window.
EEPROM Read/write (from RF Field):
Click on “Read EEPROM” to read out the configuration word.
Figure 43: AS3953 EEPROM window
7.3.14.3
E-Paper Reference Design
Figure 44 shows the window of the E – Paper Reference design.
The Reference design should be placed on the AS3911 reader.
Click in the display section of the shown E-Paper demo picture and write something in the display.
Press “Update EPD” and the E-Paper Reference design will display the made changes.
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Figure 44: AS3953 E-Paper Reference Design window
7.3.15 SL13A tab
The SL13A windows in Figure 45 & Figure 46 demonstrate the features of this smart sensory tag
IC.
The whole Cool Log command set is shown the sub – tab “General” (see Figure 45). Here it is
possible to execute after an Inventory – Command all these commands. A detailed description of
the commands is shown on the right hand side.
The “Demo” sub-tab shows the temperature measurement capability in the active or passive mode.
The temperature information can be stored in the EEPROM (non-volatile) in the active mode.
The passive mode stores the temperature in the EEPROM (volatile).
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Figure 45: SL13A General window
Figure 46: SL13A Demo window
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7.3.16 Firmware update
The firmware can be updated by the GUI once the board is connected.
In the menu button “Help” provide a menu item “Firmware Upgrade” that will guide you through the
update procedure (see Figure 47).
Figure 47: Menu --> Firmware update
After activate the Firmware Update, the GUI opens a file dialogue box which allows you to select
the bin file (see Figure 48).
Figure 48: GUI firmware selection
The GUI files can be found on the FTP server:
File location
http://www.space4ams.at/user/AS3911GP_GUI/default.php
User
GPgui
Password
hgewdt3
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8
References
Application notes:

AS3911 AN Wakeup modes 2V0

AS3911 AN Wakeup Electrodes V1

AS3911 AN Antenna Design Guide V1.4

AS3911 AN 50 Ohm single ended V2

AN PCB layout recommendation
This application notes are available on request from ams sales representatives at
www.ams.com/Contact-Us/Sales-Offices.
Standards:

ISO / IEC 14443

ISO / IEC 18092

ISO / IEC 22536

ISO / IEC 10373-6

FCC Title 47 Part 15
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9
Ordering & Contact Information
Ordering Code
Description
990600495
AS3911 Demo Kit Standard Board
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
[email protected]
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
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10 Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks
Registered. All rights reserved. The material herein may not be reproduced, adapted, merged,
translated, stored, or used without the prior written consent of the copyright owner.
Information in this document is believed to be accurate and reliable. However, ams AG does not
give any representations or warranties, expressed or implied, as to the accuracy or completeness of
such information and shall have no liability for the consequences of use of such information.
Applications that are described herein are for illustrative purposes only. ams AG makes no
representation or warranty that such applications will be appropriate for the specified use without
further testing or modification. ams AG takes no responsibility for the design, operation and testing
of the applications and end-products as well as assistance with the applications or end-product
designs when using ams AG products. ams AG is not liable for the suitability and fit of ams AG
products in applications and end-products planned.
ams AG shall not be liable to recipient or any third party for any damages, including but not limited
to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect,
special, incidental or consequential damages, of any kind, in connection with or arising out of the
furnishing, performance or use of the technical data or applications described herein. No obligation
or liability to recipient or any third party shall arise or flow out of ams AG rendering of technical or
other services.
ams AG reserves the right to change information in this document at any time and without notice.
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11 Revision Information
Initial version 1-00
Changes from previous version to current revision 1-02 (2015-Sep-07)
Changing footer
Page
1-51
Updated Figure 27
28
Updated Figure 28
29
Updated Figure 29
30
Adding Revision Information Table
51
Adding sales information
1-51
Note: Page numbers for the previous version may differ from page numbers in the current revision.
Correction of typographical errors is not explicitly mentioned.
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