RFID Reader User Manual Rev 1.0
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Design Controls
User Manual
RFID Reader Board
IFU-010-140
Welbilt
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i FCC Interference Statement (Part 15.105 (b))
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC
Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This
equipment generates uses and can radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not
occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following
measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
ii FCC Part 15 Clause 15.21
“Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to
operate the equipment”
iii FCC Part 15.19
“This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may
not cause harmful interference, and (2) this device must accept any interference received, including interference that may
cause undesired operation.”
iv ISED RSS-Gen Notice
“This device complies with Industry Canada’s licence-exempt RSSs. Operation is subject to the following two conditions:
(1) This device may not cause interference; and
(2) This device must accept any interference, including interference that may cause undesired operation of the device.”
“Le présent appareil est conforme aux CNR d’Industrie Canada applicables aux appareils radio exempts de licence.
L’exploitation est autorisée aux deux conditions suivantes :
1) l’appareil ne doit pas produire de brouillage;
2) l’appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d’en compromettre le
fonctionnement.”
v FCC RF Exposure Guidance Statement
“In order to comply with FCC/ISED RF Exposure requirements, this device must be installed to provide at least 20 cm
separation from the human body at all times.
“Afin de se conformer aux exigences d'exposition RF FCC / ISED, cet appareil doit être installé pour fournir au moins 20 cm
de séparation du corps humain en tout temps.“
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Contents
i FCC Interference Statement (Part 15.105 (b)) ......................................................................... 2
ii FCC Part 15 Clause 15.21 ......................................................................................................... 2
iii FCC Part 15.19 ........................................................................................................................ 2
iv ISED RSS-Gen Notice............................................................................................................... 2
v FCC RF Exposure Guidance Statement .................................................................................... 2
1. Purpose ........................................................................................................................ 5
2. End Product Labelling .................................................................................................. 5
3. Definitions, acronyms, and abbreviations ................................................................... 5
4. Reference Documents ................................................................................................. 5
5. Product Description ..................................................................................................... 6
5.1 System Diagram ............................................................................................................ 6
5.2 External Connections .................................................................................................... 6
5.2.1 MODBUS Connector ........................................................................................... 6
6. Hardware Description .................................................................................................. 8
6.1 Power ............................................................................................................................ 8
6.1.1 Input Power ........................................................................................................ 8
6.1.2 RF Output Power ................................................................................................ 8
6.2 ID Select Jumper ........................................................................................................... 8
6.3 Indicators ...................................................................................................................... 8
6.4 Microcontroller ............................................................................................................. 8
6.4.1 Microcontroller ................................................................................................... 8
6.4.2 Clock ................................................................................................................... 8
6.4.3 Debug/Personality Module Support ................................................................... 9
6.4.4 Reset ................................................................................................................... 9
6.5 Communication Peripherals ......................................................................................... 9
6.5.1 MODBUS Interface .............................................................................................. 9
6.5.2 SPI Interface ........................................................................................................ 9
6.6 RFID Transceiver ........................................................................................................... 9
6.7 RF Analog Multiplexor ................................................................................................ 10
6.8 Inductive Antenna Tuner ............................................................................................ 10
7. Software Description ................................................................................................. 10
7.1 Bootloader Support .................................................................................................... 10
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7.2 Microcontroller Configuration .................................................................................... 11
7.3 RFID Transceiver Configuration .................................................................................. 11
7.4 RFID Zone Scanning..................................................................................................... 11
7.5 Communication Bus Drivers........................................................................................ 12
7.5.1 MODBUS Interface ............................................................................................ 12
7.5.2 SPI Interface ...................................................................................................... 12
8. Specifications (Typical) .............................................................................................. 13
9. Appendix A................................................................................................................. 13
10. Appendix B (RF Reader Assembly Rev 2) ................................................................... 14
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1. Purpose
The purpose of this document is to describe the functionality of the RFID reader module. The intent is to provide RFID reader capability
customized for Welbilt commercial foodservice products.
2. End Product Labelling
The end product labelling shall provide the following FCC ID information for the reader module:
“Contains FCC ID: 2AQ4D-RFIDREADER”
“Contains IC: 24291-RFIDREADER”
On the ISED Canada ICES-003 Compliance Label:
“CAN ICES-3 (B)/NMB-3(B)”
3. Definitions, acronyms, and abbreviations
Abbreviation or
Term
Definition
UID
Unique Identification Code
NFC
Near Field Communication
RFID
Radio Frequency Identification
PCBA
Printed Circuit Board Assembly
CAN
Controller Area Network
PM
Personality Module
MTW
Manitowoc Foodservice
SOP
Standard Operating Procedure
4. Reference Documents
Document Name
Number
Ref
Revision
RFID Reader Board Schematic
10000100-100
[1]
3
RFID Reader Board VHC SW
[2]
0.4.0
VHC RFID Tag HRS
HRS-010-700
[3]
1.1
VHC RFID Antenna Schematic
10010005-300
[4] 1
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5. Product Description
5.1 System Diagram
Power
&
MODBUS
Program
&
PM
Module
Microcontroller
&
RFID Transceiver
RF Switch
Zone
1
Zone
2
Zone
3
Zone
4
Zone
5
Zone
12
Zone
11
Zone
10
Zone
9
Zone
8
Zone6Zone
7
Antenna
Antenna
Antenna
Antenna
Antenna
Antenna
RF Reader Board
Addressable RFID System
5.2 External Connections
5.2.1 MODBUS Connector
The power and P-BUS/C-BUS signals are located on the RJ45 “MODBUS” connector. The connector type is Molex 4320288113 or
equivalent. This connector is keyed.
Signal Name
Signal Type
Pin Number
CBUS+
RS-485
J14-1
CBUS-
RS-485
J14-2
5V_RAW_SRB
Power
J14-3
PBUS-
RS-485
J14-4
PBUS+
RS-485
J14-5
GND
Ground
J14-6
12V_RAW_SRB
Power
J14-7
GND
Ground
J14-8
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5.2.1.1 Program Connector
The connector is a Hirose DF9-11P-1V(32).
Signal Name
Signal Type
Pin Number
MCLR
Data
J15-1
3V3_VDC
Power
J15-2
AGND
Ground
J15-3
PGEDI
Data
J15-4
PGECI
Data
J15-5
10k_pullup
Data
J15-6
SPI_MOSI
Data
J15-7
SPI_SCLK
Data
J15-8
SPI_MISO
Data
J15-9
PM_CS
Data
J15-10
NC
NC
J15-11
AGND
Ground
J15-12
AGND
Ground
J15-13
5.2.1.2 RF Connector
The MMCX connector is a Molex 0734150961.
Signal Name
Signal Type
Pin Number
RF_ANT
Data
J1-1
RF_ANT_RTN
Ground
J2-2
RF_ANT_RTN
Ground
J3-3
5.2.1.3 ID Select Connector
The header connector is a TE Connectivity 5-146280-3 or equivalent.
Signal Name
Signal Type
Pin Number
ID_SEL_0
Power
J13-1
AGND
Ground
J13-2
ID_SEL_1
Data
J13-3
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6. Hardware Description
6.1 Power
6.1.1 Input Power
The RFID reader board derives all power from the 12VDC(+/-10%) and 5VDC(+10%/-5%) as defined per the MODBUS connector. The
reader generates 3V3 from the 5VDC rail using an MCP1700T LDO rated at 250mA. The 5V2 voltage is generated from the 12VDC rail
using an AZ1117LDO rated at 800mA.
6.1.2 RF Output Power
When configured for 5-V operation (see section 6.6), the RF amplifier voltage can be set from 4.3V to 5V in 100mV steps via software.
In 3-V operation, the RF amplifier can be set from 2.7V to 3.4 in 100mV steps. The typical output power at maximum setting is
17dBm@3-V operation and 23dBm@5-V operation.
6.2 ID Select Jumper
The MODBUS ID of the reader board can be set using a standard 100 mil jumper on J13 per the following table:
MODBUS ID
JUMPER POSITION
RFID_ ID1
Jumper across J13-1 and J13-2
RFID_ ID2
Jumper across J13-2 and J13-3
RFID_ ID3
No jumper installed
6.3 Indicators
The reader board provides an LED for each of the power rails; 5V2_VDC(GREEN), 3V3_VDC(GREEN).
The reader board provides a BLUE LED for each of the RF antenna zones 1 through 12 (as shown in appendix B). Each LED will illuminate
whenever a valid tag is detected on an attached RFID antenna.
The reader board provides a GREEN LED to indicate the status of the microcontroller as well as an ORANGE LED to indicate the
communication on the MODBUS.
6.4 Microcontroller
6.4.1 Microcontroller
The RFID reader board uses Microchip PN PIC24EP512GU810-I/PF in a 100 pin TQFP package. The micro has the following standard
features:
• 512kB Program Flash Memory
• 52kB RAM
• 4 Channel UART
• 2 Channel SPI
• 83 General Purpose I/O pins
6.4.2 Clock
The microcontroller is clocked externally from the signal SYS_CLOCK from the RFID transceiver.
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6.4.3 Debug/Personality Module Support
The reader board can be programmed and/or debugged from a Microchip ICD 3 module via J15. The connector is also compatible with
Manitowoc’s personality module for applications that desire external flash memory.
6.4.4 Reset
The reader board can reset by momentarily grounding (~100ms) J15-1 pin. This will cause the entire board to reset and restart the
initialization routine.
6.5 Communication Peripherals
6.5.1 MODBUS Interface
The reader board translates UART signals from the microcontroller to RS-485 levels using ST485EBDR transceivers. Both a peripheral
bus (P-BUS) and a communication bus (C-BUS) are provided. Both buses are terminated using the Manitowoc scheme shown in
Appendix A, filtered and routed to J14.
6.5.2 SPI Interface
The reader board utilizes SPI protocol (and is so configured) for communications from the microcontroller and the RFID transceiver.
The signals RFID_CS, MISO, MOSI, and SPI_CLOCK are used.
The SPI bus runs at 2MHz.
The reader board also has the capability to communicate to a PM via the same SPI bus using the PM_CS signal on the J15 connector.
6.6 RFID Transceiver
The reader board utilizes TI’s TRF7970A multiprotocol 13.56MHz RFID and NFC transceiver IC. It provides a built-in data framing engine
for several protocols including ISO15693, ISO18000-3, ISO14443A/B, and FeliCa as well as the integrated analog front end. It is also
configured for single-ended output (signal ground referenced) which facilitates multiplexing applications.
The power supply for the transceiver can be run from 5V2 or 3V3 voltage rail by populating either R1(5V2) OR R2(3V3) zero ohm
resistor.
The transceiver runs from a 13.56MHz crystal, which in turn supplies SYS_CLOCK to the microcontroller at 13.56MHz, 6.78MHz, or
3.39MHz depending on software configuration.
An impedance-matching circuit from the 4 Ohm (TX output) to 50 Ohm impedance designed for 50 Ohm tuned antennas and cabling
systems is provided on board and is shown below:
The transceiver is enabled via RFID_EN (active-high) from the microcontroller. Anytime a new tag is detected the transceiver will drive
the RFID_IRQ low and hold it until the package is read by the microcontroller.
The signals RFID_ASK and RFID_MOD are provided to microprocessor for applications that desire to use the RFID transceiver in
DIRECT_MODE. Although most applications will want to take advantage of the data format engine included in the chip.
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6.7 RF Analog Multiplexor
The reader board switches the main RF channel to any one of the 12 available RF ports using Peregrine 4 SP4T PE42440 RF switches.
This part feature ESD protection as well low series resistance and insertion loss at the 13.56MHz carrier frequency. The RF switches
are the reflective type as absorptive are not required for this application.
The active channel is selected by the microcontroller per the following table:
Zone
Conn
MUX_SEL0
MUX_SEL1
MUX_SEL2
MUX_SEL3
1
J3 1 0 1 0 2 J9 1 1 1 0
3
J10 0 1 1 0 4 J4 0 0 1 0 5 J5 1 0 0 1
6
J11 1 1 0 1
7
J12 0 1 0 1 8 J6 0 0 0 1 9 J1 1 0 0 0
10
J7 1 1 0 0
11
J8 0 1 0 0
12
J2 0 0 0 0
6.8 Inductive Antenna Tuner
Each zone provides footprints to allow tuning for a wide range of custom antennas at each RF port. The technique of tuning a particular
antenna goes beyond this specification; however the goal of the tuning circuit is to convert the inherent impedance of the antenna
loop (@13.56MHz) to match the 50 Ohm impedance of the RFID transceiver circuit.
For example the VHC (Visual Holding Cabinet) RFID antenna measures 1.5uH@13.56MHz using a network analyzer. To convert the
impedance to 50Ohm, a 68pF series capacitor along with a 12pF parallel capacitor was used to allow the antenna to resonate at
13.56MHz. This results in a matched antenna with a read range of ~5 inches in air (no conductive metal near).
7. Software Description
7.1 Bootloader Support
The bootloader program is programmed in the auxiliary program flash memory and the microcontroller is configured to reset to
auxiliary flash reset location. The application is programmed to user program flash memory and the bootloader is used to write
application updates to user program flash memory in the field without using MCU programmer devices.
The bootloader is using the peripheral bus (P-BUS) to receive firmware update packets.
On power-up the bootloader checks if the user program memory has a valid application by calculating and comparing the application
CRC16 value. If a valid application is detected then the bootloader will jump to user program memory and start the main application.
If the user program memory application is not valid then the bootloader will not start the main application and wait for receiving
firmware update packets from the master device.
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To start the bootloader application the master device command the RFID reader board to switch to bootloader program using
modbus interface (P-BUS). When the firmware update is done, the master device commands the RFID reader board to start
execution of the main application.
Each frame has address, function code, packet data and CRC16. The function codes of boot loader are as follow:
• #define MODBUS_CMD_START_APP 0x55 /* exit boot loader and start main application */
• #define MODBUS_CMD_START_BOOT 0x56 /* exit main application and start boot loader */
• #define MODBUS_CMD_WRITE_FLASH 0x57 /* write firmware data to flash memory */
• #define MODBUS_CMD_READ_OK 0x58 /* response from slave board when command is ok */
For the write flash command, the first 4 bytes are the address (in little-endian format) in flash memory and the next 128 bytes are
the data to write (128 bytes = 32 program memory words). For the other commands the packet data is not used and should filled
with 0's.
7.2 Microcontroller Configuration
The microcontroller is configured to reset to auxiliary flash program memory where the bootloader is programmed to auxiliary flash
memory.
The oscillator is configured to use external clock source where the microcontroller is clocked externally from the signal SYS_CLOCK
from the RFID transceiver. The PLL is enabled and configured to provide 120 MHz Fosc. The CPU clock (instruction execution speed)
is 60 MHz.
The watchdog timer is always enabled (by hardware) and the post-scale and pre-scale are configured so that the WDT period is
4.096 second.
The microcontroller In-Circuit Serial Programming is configured to communicate on PGEC1 and PGED1. The JTAG is disabled.
7.3 RFID Transceiver Configuration
The RFID transceiver is configured to provide 3.39 MHz system clock for MCU. The modulation Type and depth is set to OOK (100%).
The RFID Transceiver regulators configuration is set automatic setting - VDD_RF = 4.9 V, VDD_A = 3.4 V, VDD_X = 3.4 V.
The RFID is configured to operate in 5V VIN voltage range and to operate in RFID mode. The RFID is configured to use ISO15693
protocol.
In RFID Reader software, the RFID transceiver is controlled by ReaderController active object. The software is reading the first 2
blocks in user data area from the RFID tag using ISO15693 READ SINGLE BLOCK command.
7.4 RFID Zone Scanning
The RFID zone scanning is done by selecting the analog input to read by controlling the output status of MUX_SEL0 to MUX_SEL3
signals and then trigger the ReaderController to start read the tag on the selected channel. The RFID zone scanning is controlled by
SystemController active object. The system controller reads channels sequentially and each channel is read twice, the first time
block 0 is read and the second time block 1 is read from user data memory in the RFID tag.
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When a read is completed successfully, SystemController update the modbus registers with the read value. If no tag is detected then
the channel data is set to 0's.
7.5 Communication Bus Drivers
7.5.1 MODBUS Interface
The UART4 module is configured to be used for modbus communication on the P-BUS. The UART4 is configured to run at 115200
baud rate, no parity and one stop bit.
The driver is developed to be interrupt driven and non-blocking functions to be suitable for use with the QP frame work. Timer
module is also imported from the same project where this timer module is required for the UART driver operations.
The RFID reader board is a slave modbus device. The modbus interface is implemented in QpModbusServer active object.
7.5.2 SPI Interface
The SPI port is used for communication with the RFID transceiver chip. The SPI driver is used and accessed by ReaderController
active object to read and write to the RFID transceiver chip.
The SPI port is configured to run at 2MHz, 8 bit data, SPI clock mode is set to mode 0 (Serial output data changes on transition from
idle clock state to active clock state and Idle state for clock is a low level; active state is a high level) and Input data is sampled at end
of data output time.
The SPI driver is developed to be interrupt driven and non-blocking functions to be suitable for use with the QP frame work.
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8. Specifications (Typical)
Protocol
ISO15693
Interface
Modbus RS-485 115kbit@8N1
RF Output Power (13.56MHz)
100mW@3.3VDC or 200mW@5VDC
Input Power
12VDC and 5VDC
Operating/Storage Temp
0 to 70°C (10 to 95% Relative Humidity – non-condensing)
9. Appendix A
RS-485 MODBUS Termination Scheme
10k
10k
1k
A (+)
5VDC
B (-)
Figure 2: ETC CCA MODBUS termination
Figure 3: ETC EIA/TIA-485 C/P-Bus 2x2W Modbus 8P8C Plug
Pin
Name
EIA/TIA-485
Description
1
CDA
A/A'
C-Bus Data (+)
2
CDB
B/B'
C-Bus Data (-)
14
3
VDC
--
+5 VDC
4
PDB
B/B'
P-Bus Data (-)
5
PDA
A/A'
P-Bus Data (+)
6
GND C Signal and Supply Common
7
12VDC
--
Auxiliary Power
8
GND
--
Auxiliary Power Common
10. Appendix B (RF Reader Assembly Rev 2)
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