Getac Technology ZX70U User Manual
www.ams.com
Revision 1.0 / 2012/06/26
Application Note: UHF RFID Fermi Reader
HW
AS3993
UHF RFID Single Chip Reader EPC
Class1 Gen2 Compatible
-Description
AS3993 – AN13 – Received Signal Str engt h In dicat or (RS SI)
www.ams.com
Revision 2.0 / 6/22/12
page 1/17
7
7
8
5.4 Programming Interface Description........................................................................... 9
10
10
11
6.4 OAD Pins ............................................................................................................... 16
Table of Contents
Introduction .......................................................................................................................... 2
1.
2. Key Features ....................................................................................................................... 3
3. Applications ......................................................................................................................... 4
4. Reader System Description .................................................................................................. 5
5 Interfaces ............................................................................................................................. 7
5.1 USB ..........................................................................................................................
5.2 UART Interface .........................................................................................................
5.3 Pin Header Interface Description ..............................................................................
6 Reader Part ....................................................................................................................... 10
6.1 RF Tracks – Impedance Calculation .......................................................................
6.2 Reader Part – PCB Stackup ...................................................................................
6.3 Reader Part – Schematics ......................................................................................
7 Controller Part .................................................................................................................... 16
Copyright .................................................................................................................................. 17
Disclaimer ................................................................................................................................. 17
Figure 1 - Reader Part ......................................................................................................................... 5
Figure 2 - Controller Part ..................................................................................................................... 6
Figure 3 - Pin Header Position (all dimensions in mm) ....................................................................... 8
Figure 4 - Programming Interface (all dimension s in m m ) .................................................................. 9
Figure 5 - RF Tracks - Impedance Calculation (dimensions in mil) .................................................. 10
Figure 6 - RF Part - PCB Stackup ..................................................................................................... 10
Figure 7 - Schematic Reader Section ............................................................................................... 11
Figure 8 - Schematic Loop Filter ....................................................................................................... 11
Figure 9 - Reader Indicator LEDs ...................................................................................................... 12
Figure 10 - Schematic Balun Section ................................................................................................ 13
Figure 11 - Schematic PA Section .................................................................................................... 14
Figure 12 - Schematic Directional Coupler........................................................................................ 15
Figure 13 - OAD Pads ....................................................................................................................... 16
Figure 14 - Schematic MCU Section ................................................................................................. 16
AS3993 – AN13 – Received Signal Str engt h In dicat or (RS SI)
www.ams.com
Revision 2.0 / 6/22/12
page 2/17
1. Introduction
The FERMI Reader is a small form factor and low costs EPC Class 1 Gen 2 UHF RFID
demonstration reader system. Leveraging AS3993 UHF RFID Reader IC, provides close to the
industry’s lowest BOM cost, best in class power consumption with the least amount of
complexity.
Second only to ams FERMI design the low r eader BOM enables UHF RFID markets that have
previously been out of reach due to cost restrain ts. With regards to overall cost vs. performance
the FERMI UHF RFID demo reader is unmatched in the indus try.
With an external PA delivering up to 22 dBm, it is ideally suited for those applications that have
similar cost constraints but require that ex tra power
The FERMI demo reader comes in two parts namely the analogue (reader) and digital
(controller) parts. The user can separate the two stacked boards to fully prove out their own RF
and digital parts. With this se t up it also means the user can eva luate the suitability of RFID in
their current system.
The reader portion is designed such that it can b e easily connected to a host MCU via SPI. The
high level of integration found on the AS3993 UHF RFID Reader IC allows for minimal code
loading and quick implementation.
The designs come with free, fully portable code and all Gerber data and sche matics. This allows
for a quick, trouble free design in.
AS3993 – AN13 – Received Signal Str engt h In dicat or (RS SI)
www.ams.com
Revision 2.0 / 6/22/12
page 3/17
2. Key Features
• Interface
o Between the Controller and Host Computer: US B (opt ional U ART)
o Between the Controller and the AS3993 is SPI via a low cost pin header
connection
o Between the RF board and the Antenna we use a U .FL (5 0 O hm) SMA ( Male)
• 5V power suppl y from USB.
• GUI
o Adjust Output Power
o Adjust Receive – Sensitivity
o Adapt to different frequency schemes (FCC ETSI)
o Change Gen2 specific parameters like BLF, Coding , Ant i-Collision Slots, …
o Diagnostic Features: RSSI Measurement, Reflected Power Measure ment
o Support for sending AS3993 related direc t commands
o Advanced Tag Manipulations: R/W to differen t memory b anks, define passwords
o Associate tags with other applications like me dia p layer
o View and easily manipulate register settings with a dvance tool tip te xt.
• Low Power Consu mption: com plete reader s ystem is onl y 780mW (typ), 830mW
(max)
• Fully Gen 2 co mpliant, ISO 18000-6b & 6c
• Differen tial T X chip-output configuration
• Differential RX chip-input configuration
• External p ower a mplifier RF2 172
• Maximum output power 22 dBm scalab le in 2 0 s teps
• Low cost MCU: Microchip (PIC24FJ64GB004)
• Indicator LEDs
AS3993 – AN13 – Received Signal Str engt h In dicat or (RS SI)
www.ams.com
Revision 2.0 / 6/22/12
page 4/17
3. Applications
Typical applications for the FERMI demo reader inc lude :
• Embedded Consumer Applications
• Mobile Applicat ions (L ow P ower Handhe ld , PDA’s, Smart P hones)
• Embedded Industrial Applications
• Gaming
• Desk top readers
• Low/Mid powered modules
AS3993 – AN13 – Received Signal Str engt h In dicat or (RS SI)
www.ams.com
Revision 2.0 / 6/22/12
page 5/17
1
3
2
5
4
6
7
8
9
4. Reader System Description
Figure 1 - Reader Part
1. AS3993 UHF RFID reader IC (ams)
2. Balun 2:1 (Johanson Technology)
3. Power Amplifier RF2172 (RFMD)
4. Directional coupler / Low pass filter combination (Joh anson Techn ology)
5. U.FL antenna port (Hirose)
6. Loop Filter
7. OAD pins for debugging purposes
8. Balun 2:1 (Johanson Technology)
9. Crystal 20 MHz +/- 10ppm
Loading...