APPLICATION NOTE
Atmel AVR2162: REB233SMAD – Hardware User Manual
8-bit Atmel Microcontrollers
Features
•
High-performance 2.4GHz RF-CMOS Atmel® AT86RF233 radio transceiver
targeted for IEEE® 802.15.4, ZigBee®, ZigBee RF4CE, 6LoWPAN and ISM
applications
•
Industry leading 101dB linkbudget
•
Ulta-low current consumption
•
Ultra-low supply voltage (1.8V to 3.6V)
•
•
•
•
Hardware supported antenna diversity
RF reference design and high-performance evaluation platform
Interfaces to several of the Atmel microcontroller development platforms
Board information EEPROM
•
MAC address
•
Board identification, features, and serial number
•
Crystal calibration values
Introduction
This manual describes the REB233SMAD radio extender board supporting antenna
diversity in combination with the Atmel AT86RF233 radio transceiver. Detailed
information is given in the individual sections about the board functionality, the board
interfaces, and the board design.
The REB233SMAD connects directly to the REB controller base board (REB-CBB),
or can be used as an RF interface in combination with one of the Atmel
microcontroller development platforms. The REB233SMAD together with a
microcontroller forms a fully functional wireless node.
Figure 1.
REB233SMAD Radio Extender Board.
42006B−AVR−07/2012
Table of Contents
1. Disclaimer ............................................................................................ 3
2. Overview .............................................................................................. 3
3. Functional description .......................................................................... 3
3.1
Interface connector specification ....................................................................... 4
3.1.1
Atmel ATmega1281 configuration ....................................................... 4
3.1.2
Atmel ATmega644 configuration ......................................................... 5
3.2
ID EEPROM ...................................................................................................... 6
3.3
Supply current sensing...................................................................................... 7
3.4
Radio transceiver reference clock ..................................................................... 8
3.5
RF section ......................................................................................................... 8
4. PCB layout description ......................................................................... 9
4.1
PCB detail 1 – balanced RF pin fan out .......................................................... 10
4.2
PCB detail 2 – RF switch ................................................................................ 11
4.3
PCB detail 3 – crystal routing .......................................................................... 11
4.4
PCB detail 4 – transceiver analog GND routing .............................................. 12
4.5
PCB detail 5 – digital GND routing and shielding ............................................ 13
4.6
PCB detail 6 – transceiver RF tuning .............................................................. 14
4.7
Antenna connection ........................................................................................ 15
5. Mechanical description ...................................................................... 16
6. Electrical characteristics .................................................................... 17
6.1
Absolute maximum ratings .............................................................................. 17
6.2
Recommended operating range ...................................................................... 18
6.3
Current consumption ....................................................................................... 18
6.4
Duty cycle requirements .................................................................................. 19
7. Abbreviations ..................................................................................... 19
Appendix A.
PCB design data ........................................................... 20
A.1
Schematic ....................................................................................................... 20
A.2
Assembly drawing ........................................................................................... 21
A.3
Bill of materials ................................................................................................ 21
Appendix B.
Radio certification .......................................................... 23
B.1
United States (FCC) ........................................................................................ 23
B.2
Europe (ETSI) ................................................................................................. 24
B.3
Approved antenna ........................................................................................... 24
8. References ......................................................................................... 25
9. Revision history REB233SMAD PCBA .............................................. 26
10. EVALUATION BOARD/KIT IMPORTANT NOTICE ........................... 27
Atmel AVR2162: REB233SMAD – Hardware User Manual [APPLICATION NOTE]
42006B−AVR−07/2012
2
1.
Disclaimer
Typical values contained in this application note are based on simulations and testing of individual examples.
Any information about third-party materials or parts was included in this document for convenience. The vendor may
have changed the information that has been published. Check the individual vendor information for the latest changes.
2.
Overview
The radio extender board is assembled with an Atmel AT86RF233 radio transceiver
[1]
and equipped with two SMA
connectors to support antenna diversity. External antennas can be connected to the SMA ports as well as RF
measurement equipment for performance evaluation of the radio transceiver. The radio transceiver is able to switch
between these two antenna ports to select the best receiving path in harsh multipath environments.
The radio extender board was designed to interface to the Atmel microcontroller development or evaluation platforms
(for example, Atmel STK®500). The microcontroller platform in combination with the REB provides an ideal way to:
•
•
•
Evaluate the outstanding radio transceiver performance, such as the excellent receiver sensitivity achieved at
ultra-low current consumption
Test the radio transceiver’s comprehensive hardware support of the IEEE 802.15.4™-2011 standard
Test the radio transceiver’s enhanced feature set, which includes antenna diversity, AES, high data rate
modes and reduce power consumption modes
Figure 2-1
shows a development and evaluation setup using the REB controller base board (REB-CBB)
[2]
in
combination with the REB233SMAD radio extender board; via SMA connectors which are assembled with quarter wave
rotate and tilt antennas.
Figure 2-1. The REB233SMAD connected to a REB-CBB.
3.
Functional description
The block diagram of the REB233SMAD radio extender board is shown in
Figure 3-1.
The power supply pins and all
digital I/Os of the radio transceiver are routed to the 2 × 20-pin expansion connector to interface to a power supply and
a microcontroller.
Atmel AVR2162: REB233SMAD – Hardware User Manual [APPLICATION NOTE]
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The Atmel AT86RF233 antenna diversity (AD) feature supports the control of two antennas which can be assembled on
top of the SMA connectors. A digital control pin (DIG1) is used to control an external RF switch selecting one of the two
antennas. During the RX listening period, the radio transceiver continuously switches in between the two antennas
autonomously, without the need for microcontroller interaction, if the AD feature is enabled
[1].
Once an IEEE 802.15.4
synchronization header is detected, the antenna providing sufficient signal quality is selected to receive the remaining
frame. This ensures reliability and robustness, especially in harsh environments with strong multipath fading effects
[4].
Board-specific information such as board identifier, the node MAC address, and production calibration values are stored
in an ID EEPROM. The SPI bus of the EEPROM is shared with the radio transceiver’s interface.
Figure 3-1. REB233SMAD block diagram.
JP1
DEVDD
GND
Protection
TP7
TP6
X2
DIG3
DIG4
RSTN
RF-
Switch
Balun
RFP
DIG2
AT86RF233
RFN
IRQ
SLPTR
CLKM
X3
4
XTAL1
XTAL2
DIG1
DIG2
SPI
XTAL
REB233SMAD
3.1
Interface connector specification
The REB is equipped with a 2 × 20-pin, 100mil, expansion connector, X1. The pin assignment enables a direct interface
to the REB-CBB
[2].
Further, the interface connects to the Atmel STK500/501 microcontroller development platform to
enable support for various Atmel 8-bit AVR® microcontrollers.
The REB (2 × 20-pin X1 connector) is preconfigured to interface to an STK501 with an Atmel ATmega1281 or a
Controller Base Board with an Atmel ATxmega 256A3 respectively.
To operate the REB with an Atmel ATmega644 on STK500, the 0Ω resistors R10 through R18 must be removed and
re-installed on the board manually as resistors R20 through R28 (see
Appendix A).
Other microcontroller development platforms need to be interfaced using a special adapter board.
3.1.1
Atmel ATmega1281 configuration
Table 3-1.
Pin#
1
3
5
7
9
11
Default expansion connector mapping (ATmega1281 configuration).
Pin#
2
4
6
8
10
12
Function
GND
n.c.
n.c.
n.c.
n.c.
n.c.
Function
GND
n.c.
n.c.
n.c.
n.c.
n.c.
EXPAND1
ID
EEPROM
Atmel AVR2162: REB233SMAD – Hardware User Manual [APPLICATION NOTE]
42006B−AVR−07/2012
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Pin#
13
15
17
19
21
23
25
27
29
31
33
35
37
39
Note:
Function
n.c.
n.c.
n.c., optionally XT1 (MCLK)
(1)
V
CC
GND
PB7 (open)
PB5 (RSTN)
PB3 (MISO)
PB1 (SCLK)
PD7 (TP1)
PD5 (TP2)
PD3 (TP3)
PD1 (TP4)
GND
Pin#
14
16
18
20
22
24
26
28
30
32
34
36
38
40
Function
n.c.
n.c.
n.c.
V
CC
GND
PB6 (open)
PB4 (SLPTR)
PB2 (MOSI)
PB0 (SEL)
PD6 (MCLK)
PD4 (DIG2)
PD2 (open)
PD0 (IRQ)
EE#WP (write protect EEPROM)
1.
Possible by retrofitting a 0R assembly.
3.1.2
Atmel ATmega644 configuration
Table 3-2.
Pin#
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
Note:
Expansion connector mapping when assembled for ATmega644.
Pin#
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
Function
GND
n.c.
n.c.
n.c.
n.c.
n.c.
n.c.
n.c.
n.c.
V
CC
GND
PB6 (MISO)
PB4 (SEL)
PB2 (RSTN)
PB0 (open)
PD6 (DIG2)
PD4 (open)
PD2 (IRQ)
PD0 (open)
EE#WP (write protect EEPROM)
Function
GND
n.c.
n.c.
n.c.
n.c.
n.c.
n.c.
n.c.
n.c., optionally XT1 (MCLK)
(1)
V
CC
GND
PB7 (SCLK)
PB5 (MOSI)
PB3 (open)
PB1 (MCLK)
PD7 (SLPTR)
PD5 (TP2)
PD3 (TP3)
PD1 (TP4)
GND
1.
Possible by retrofitting a 0R assembly.
Atmel AVR2162: REB233SMAD – Hardware User Manual [APPLICATION NOTE]
42006B−AVR−07/2012
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