User's Manual

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Atmel AVR2080: REB231FE2 - Hardware User's

Manual

Features

• High-performance, 2.4GHz, RF-CMOS Atmel

AT86RF231 radio transceiver targeted

for IEEE

802.15.4, ZigBee

, and ISM applications

- Industry leading 104dB link budget

- Ultra-low current consumption

- Ultra-low supply voltage (1.8V to 3.6V)

• High-performance, fully integrated 2.4GHz RF Front End Module SE2431L

• Hardware supported antenna diversity

• RF reference design and high-performance evaluation platform

• Interfaces to various Atmel microcontroller development platforms

• Board information EEPROM

- MAC address

- Board identification, features, and serial number

- Crystal calibration values

1 Introduction

This manual describes the Atmel REB231FE2 radio extender board supporting

increased TX output power and RX sensitivity as well as antenna diversity. The

board is designed using the AT86RF231 radio transceiver in combination with the

Skyworks SE2431L RF front end module (FEM). Detailed information is given in

the individual sections about the board functionality, the board interfaces and the

board design.

The REB231FE2 connects directly to the REB controller base board (REB-CBB),

or can be used as an RF interface in combination with an Atmel microcontroller

development platform. The REB231FE2 together with a microcontroller forms a

fully functional wireless node.

Figure 1-1. Top and bottom view of the REB231FE2.

8-bit Atmel

Microcontrollers

Application Note

Rev. 8479A-AVR-01/12

Summary of content (27 pages)

PAGE 1
Atmel AVR2080: REB231FE2 - Hardware User's Manual Features • High-performance, 2.4GHz, RF-CMOS Atmel® AT86RF231 radio transceiver targeted for IEEE® 802.15.4, ZigBee®, and ISM applications - Industry leading 104dB link budget - Ultra-low current consumption - Ultra-low supply voltage (1.8V to 3.6V) • High-performance, fully integrated 2.
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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.
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Atmel AVR2080 4 Functional description The block diagram of the Atmel REB231FE2 radio extender board is shown in Figure 4-1. 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. The Atmel AT86RF231 antenna diversity (AD) feature supports the control of two antennas (ANT0/ANT1). A digital control pin (DIG1) is used to control an external RF switch selecting one of the two antennas.
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.1.1 REB-CBB (Atmel ATxmega256A3) and Atmel STK501 (Atmel ATxmega1281) configuration Table 4-1. Default expansion connector mapping. Pin# Function Pin# Function 1 GND 2 GND 3 n.c. 4 n.c. 5 n.c. 6 n.c. 7 n.c. 8 n.c. 9 n.c. 10 n.c. 11 n.c. 12 n.c. 13 n.c. 14 n.c. 15 n.c. 16 n.c. 17 XT1 (MCLK) 18 n.c.
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Atmel AVR2080 Pin# Function Pin# Function 29 PB1 (MCLK) 30 PB0 (open) 31 PD7 (SLPTR) 32 PD6 (DIG2) 33 PD5 (TP2) 34 PD4 (open) 35 PD3 (TP3) 36 PD2 (IRQ) 37 PD1 (TP4) 38 PD0 (open) 39 GND 40 EE#WP (write protect EEPROM) 4.2 ID EEPROM To identify the board type by software, an optional identification (ID) EEPROM is populated. Information about the board, the node MAC address and production calibration values are stored here.
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Figure 4-3 shows a detailed description of the EEPROM data structure. Table 4-3. ID EEPROM mapping. Address Name Type Description 0x00 MAC address uint64 MAC address for the 802.15.4 node, little endian byte order 0x08 Serial number uint64 Board serial number, little endian byte order 0x10 Board family uint8 Internal board family identifier 0x11 Revision uint8[3] Board revision number ##.##.
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Atmel AVR2080 4.3 Supply current sensing A jumper, JP1, is placed in the supply voltage trace to offer an easy way for current sensing of active components one the Atmel REB231FE2, see Figure 4-4. The power supply pins of the radio transceiver and FEM are protected against overvoltage stress and reverse polarity at the EXPAND1 pins (net CVTG, net DGND) using a Zener diode (D1) and a thermal fuse (F1) (see appendix A.1).
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applied to TRX register XOSC_CTRL (0x12), is stored in the onboard EEPROM (see Section 4.2). The reference frequency is also available at pin CLKM of the radio transceiver and, depending on the related register setting; it is divided by an internal prescaler. CLKM clock frequencies of 16MHz, 8MHz, 4MHz, 2MHz, 1MHz, 250kHz, or 62.5kHz are programmable (refer to [1]). The CLKM signal is filtered by a low-pass filter to reduce harmonic emissions within the 2.4GHz ISM band.
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Atmel AVR2080 In transmit mode, nominal antenna port transmit output power is +20dBm for Atmel AT86RF231 sub-register setting TX_PWR = 0x0A at EVDD = 3.0V nominal supply voltage. Second and third harmonics levels are less than -42dBm/MHz. Transmit output power level is adjusted using the AT86RF231 TX output power, controlled via register bits TX_PWR. The supply voltage can be increased to 3.6V to further increase transmit output power.
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5 PCB layout description This section describes critical layout details to be carefully considered during a PCB design. The PCB design requires an optimal solution for the following topics: • Create a solid ground plane for the antenna.
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Atmel AVR2080 5.1 PCB detail 1 – balanced RF pin fan out Figure 5-2. Board layout – SE2431L layout. The SE2431L (U1) and associated circuitry follow a standard Skyworks Solutions recommended layout to achieve specified RF performance. The SE2431L requires a central PCB ground pad which is completely relieved of solder resist and has a grid of 15 ground vias [9]. This is essential to achieve good RF performance and adequate thermal conduction, especially in transmit mode.
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Figure 5-3. Board layout – XTAL section. When designing applications for very harsh environments, for example where the radio transceiver is close to mains power lines and burst and surge requirements already dictate special provisions in the design, the above reference crystal design might not work well. In this case, the reference crystal ground is to be directly connected to top and bottom layers. 5.
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Atmel AVR2080 Each ground pin should be connected to the bottom plane with at least one via. Move the vias as close to the IC as possible. It is always desired to integrate the single-pin ground connections into polygon structures after a short distance. Top, bottom, and, on multilayer boards, the inner ground planes, should be tied together with a grid of vias. When ground loops are smaller than one tenth of the wavelength, it is safe to consider this as a solid piece of metal.
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6 Mechanical description The Atmel REB231FE2 is manufactured using a low-cost, two-layer printed circuit board. All components and connectors are mounted on the top side of the board. The format was defined to fit the EXPAND1 connector on the REB-CBB and Atmel AVR STK500 / STK501 microcontroller evaluation board. The upright position is chosen for best antenna performance. Figure 6-1. Mechanical outline. 57.
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Atmel AVR2080 7 Electrical characteristics 7.1 Absolute maximum ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the board. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this manual are not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
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7.4 Transmitter characteristics Test conditions (unless otherwise stated): VDD = 3.0V, fRF = 2.45GHz, TOP = 25°C, TX_PWR=0xA, X2 conducted Table 7-4. Transmitter characteristics. No. Parameter Condition 7.4.1 TX Output Power 7.4.2 Output Power Range 7.4.3 Harmonics 7.4.4 Spurious Emissions Note: Minimum Ch11 … 25, Ch26 (1) +5 average, worst case 4f0 Typical +20 Maximum +23.5 (2) Unit dBm 15 18 dB -50 -44 dBm/MHz tbd. dBm 1.
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Atmel AVR2080 8 Abbreviations AD - Antenna diversity AES - Advanced encryption standard BB - Baseband REB-CBB - REB-Controller base board ETSI - European Telecommunications Standards Institute FCC - Federal Communications Commission FEM - Front end module ISM - Industrial, scientific and medical (frequency band) LDO - Low-dropout LNA - Low-noise amplifier MAC - Medium access control MCU - Microcontroller unit PA - Power amplifier PCB - Printed Circuit Board PDI -
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S/N S/N1 1 R2 nc SLPTR RSTN TP TP4 TP TP3 TP TP TP2 TP1 nc R3 R7 1M00 DEVDD 350mA F1 nc R28 nc R27 nc R26 nc R25 nc R24 nc R23 nc R22 nc R21 nc R20 DGND DEVDD U6B GND VCC 4 2 NC7WV04P6X_NL 3 2 5 6 U6A NC7WV04P6X_NL 1 BZG05C3V9 D1 IRQ SEL MOSI MISO SCK MCLK SLPTR DIG2 RSTN JP1 XT1 CVTG DGND PB7 PB5 PB3 PB1 PD7 PD5 PD3 PD1 DGND RST PD0 PB0 PB2 PB3 PB1 PD6 PB4 PD4 PB5 6 1 5 U4B GND VCC 1 1 2 3 7 NC7WP32K8X_NL 5 6 4 8 2 R11 0
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Atmel AVR2080 A.2 Assembly drawing Figure 8-2. Atmel REB231FE2 assembly drawing. 1 C C 2 C7 C8 C9 C10 C20 C21 C22 A2 C3 C4 C5 C6 C13 C14 C15 A1 X2 SH1 X3 C12 C L 25 C 3 40 C11 L1 R9 D1 F1 eg. ATmega 644 C30 R12 R22 R10 R20 R16 R26 R15 R25 JP1 U6 U4 R7 R17 R27 Q1 R2 R3 C35 1 U5 1 R14 R24 R13 R23 R28 R11 R21 TP4 TP3 TP2 TP1 R18 U3 R8 R1 C37 C36 C34 C33 C18 TP5 C29 C32 40 TP7 C28 C26 C31 U1 TP6 1 C39 C42 R31 R32 C38 R19 R29 R30 R6 C43 C27 L2 C41 eg.
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A.3 Bill of materials Table 8-1. Bill of materials. Qty. Designator Description Footprint Manuf. Part# Manufacturer Comment 2 X2, X3 RF connector MS147 SMA CL358-150-5-06 Hirose MS147 1 X1 Pin header 2×20 90 degree JP_2x20_90°_ Top_Invers 1007-121-40 CAB HEADER-20X2 1 U5 EEPROM MiniMap-8-2X3 AT25010B-MAHL-T Atmel AT25010B 1 U4 Logic gate MO-187 NV7WP32K8X Fairchild NC7WP32K8X 1 U3 802.15.4 2.
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Atmel AVR2080 Appendix B – Radio certification The Atmel REB231FE2, mounted on a REB controller base board (REB-CBB), has received regulatory approvals for modular devices in the United States and ensures compliance in European countries. B.1 United States (FCC) Compliance Statement (Part 15.19) The device complies with Part 15 of the FCC rules.
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B.2 Europe If the device is incorporated into a product, the manufacturer must ensure compliance of the final product to the European harmonized EMC and low-voltage/safety standards. A Declaration of Conformity must be issued for each of these standards and kept on file as described in Annex II of the R&TTE Directive.
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Atmel AVR2080 References [1] AT86RF231: Low Power, 2.4GHz Transceiver for ZigBee, IEEE 802.15.4, 6LoWPAN, RF4CE, SP100, WirelessHART and ISM Applications; Datasheet; Rev. 8111B-MCU Wireless-02/09; Atmel Corporation. [2] Atmel AVR2042: REB Controller Base Board – Hardware User Guide; Application Note; Rev. 8334A-AVR-05/11; Atmel Corporation. [3] AVR2021: AT86RF231 Antenna Diversity; Application Note; Rev. 8158B-AVR07/08; Atmel Corporation. [4] IEEE Std 802.15.
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EVALUATION BOARD/KIT IMPORTANT NOTICE This evaluation board/kit is intended for use for FURTHER ENGINEERING, DEVELOPMENT, DEMONSTRATION, OR EVALUATION PURPOSES ONLY. It is not a finished product and may not (yet) comply with some or any technical or legal requirements that are applicable to finished products, including, without limitation, directives regarding electromagnetic compatibility, recycling (WEEE), FCC, CE or UL (except as may be otherwise noted on the board/kit).
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Atmel AVR2080 9 Table of contents 1 Introduction ...................................................................................... 1 2 Disclaimer......................................................................................... 2 3 Overview ........................................................................................... 2 4 Functional description..................................................................... 3 4.1 Interface connector specification................................
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Revision History................................................................................ 23 EVALUATION BOARD/KIT IMPORTANT NOTICE ........................... 24 9 Table of contents ...........................................................................
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Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: (+1)(408) 441-0311 Fax: (+1)(408) 487-2600 www.atmel.com Atmel Asia Limited Unit 01-5 & 16, 19F BEA Tower, Milennium City 5 418 Kwun Tong Road Kwun Tong, Kowloon HONG KONG Tel: (+852) 2245-6100 Fax: (+852) 2722-1369 Atmel Munich GmbH Business Campus Parkring 4 D-85748 Garching b. Munich GERMANY Tel: (+49) 89-31970-0 Fax: (+49) 89-3194621 Atmel Japan 16F, Shin Osaki Kangyo Bldg.