APPLICATION NOTE Atmel AVR2080: REB231FE2 – Hardware User’s Manual 8-bit Atmel AVR Microcontrollers 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 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. Top and bottom view of the REB231FE2. 8479B−AVR−07/2012 Table of Contents 1. Disclaimer ............................................................................................ 3 2. Overview .............................................................................................. 3 3. Functional description .......................................................................... 4 3.1 Interface connector specification ....................................................................... 4 3.1.1 REB-CBB (Atmel ATxmega256A3) and Atmel STK501 (Atmel ATxmega1281) configuration .............................................................. 5 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 ......................................................................................................... 9 4. PCB layout description ....................................................................... 10 4.1 PCB detail 1 – balanced RF pin fan out .......................................................... 11 4.2 PCB detail 2 – crystal routing .......................................................................... 12 4.3 PCB – analog GND routing ............................................................................. 12 4.4 PCB – digital GND routing .............................................................................. 13 4.5 PCB – GND plane ........................................................................................... 13 4.6 Ceramic antenna design and tuning................................................................ 13 5. Mechanical description ...................................................................... 14 6. Electrical characteristics .................................................................... 15 6.1 Absolute maximum ratings .............................................................................. 15 6.2 Recommended operating range ...................................................................... 15 6.3 Current consumption ....................................................................................... 15 6.4 Transmitter characteristics .............................................................................. 16 6.5 Receiver characteristics .................................................................................. 16 7. Abbreviations ..................................................................................... 17 Appendix A. PCB design data ........................................................... 18 A.1 Schematic ....................................................................................................... 18 7.2 Assembly drawing ........................................................................................... 19 A.2 Bill of materials ................................................................................................ 20 Appendix B. Radio certification .......................................................... 21 B.1 United States (FCC) ........................................................................................ 21 B.2 Europe ............................................................................................................ 21 Appendix C. References .................................................................... 23 Appendix D. Revision history ............................................................. 24 Appendix E. EVALUATION BOARD/KIT IMPORTANT NOTICE....... 25 Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−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 AT86RF231 radio transceiver [1], a Skyworks SE2431L FEM [9] and two ceramic antennas, demonstrating an increased link budget together with hardware-based antenna diversity, improving radio link robustness in harsh environments significantly [3]. The radio extender board was designed to interface to an Atmel microcontroller development platform. The microcontroller board 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 standard Test the radio transceiver’s enhanced feature set, which includes antenna diversity, AES, high data rate modes and other functions The photograph in Figure 2-1 shows a development and evaluation setup using the REB-CBB [2] in combination with the Atmel REB231FE2 radio extender board. Figure 2-1. The REB231F2 connected to a REB-CBB. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 3 3. Functional description The block diagram of the Atmel REB231FE2 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. 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. During the RX listening period, the radio transceiver switches between the two antennas autonomously, without the need for microcontroller interaction, if the AD algorithm is enabled. Once an IEEE 802.15.4 synchronization header is detected, an 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. 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. REB231FE2 block diagram. TP7 VDD DIG3 ANT2 TP6 VDD AT86RF231 CLKM DIG2 DIG1 XTAL2 XTAL1 ANT1 IRQ SLPTR RFN 4 SPI EXPAND1 LPF DIG2 RFP 50R X2 Protection VSS RSTN LPF SE2431L X3 VDD DIG4 ID EEPROM XTAL 3.1 Interface connector specification The REB is equipped with a 2 × 20-pin, 100mil expansion connector. The pin assignment enables a direct interface to the REB-CBB [2]. Further, the interface connects to the Atmel STK®500/501 microcontroller development platform to enable support for various Atmel 8-bit AVR® microcontrollers. The REB is preconfigured to interface to the REB-CBB and STK501 with an Atmel ATmega1281. If an Atmel ATmega644 is used as the microcontroller, the 0Ω resistors R10 through R18 must be removed and reinstalled on the board manually as resistors R20 through R28 (see Appendix A.1). Other microcontroller development platforms need to be interfaced using dedicated adapter boards. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 4 3.1.1 REB-CBB (Atmel ATxmega256A3) and Atmel STK501 (Atmel ATxmega1281) configuration Table 3-1. Pin# 3.1.2 Default expansion connector mapping. 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. 19 VCC 20 VCC 21 GND 22 GND 23 PB7 (open) 24 PB6 (open) 25 PB5 (RSTN) 26 PB4 (SLPTR) 27 PB3 (MISO) 28 PB2 (MOSI) 29 PB1 (SCLK) 30 PB0 (SEL) 31 PD7 (TP1) 32 PD6 (MCLK) 33 PD5 (TP2) 34 PD4 (DIG2) 35 PD3 (TP3) 36 PD2 (open) 37 PD1 (TP4) 38 PD0 (IRQ) 39 GND 40 EE#WP (write protect EEPROM) Atmel ATmega644 configuration Table 3-2. Pin# Expansion connector mapping when assembled for ATmega644. 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. 19 VCC 20 VCC 21 GND 22 GND 23 PB7 (SCLK) 24 PB6 (MISO) Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 5 Pin# 3.2 Function Pin# Function 25 PB5 (MOSI) 26 PB4 (SEL) 27 PB3 (open) 28 PB2 (RSTN) 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) 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. An Atmel AT25010B [8] with 128 × 8bit organization and SPI bus is used because of its small package and low-voltage / low-power operation. The SPI bus is shared between the EEPROM and the transceiver. The select signal for each SPI slave (EEPROM, radio transceiver) is decoded with the reset line of the transceiver, RSTN. Therefore, the EEPROM is addressed when the radio transceiver is held in reset (RSTN = 0) (see Figure 3-2). Figure 3-2. EEPROM access decoding logic (Atmel ATmega1281 configuration). PB5 (RSTN) PB0 (SEL) RSTN >1 PB1..3 (SPI) SEL# /RST /SEL Transceiver AT86RF231 SPI >1 #CS On-Board EEPROM The EEPROM data are written during board production testing. A unique serial number, the MAC address (1), and calibration values are stored. These can be used to optimize system performance. Final products do not require this external ID EEPROM. All data can be stored directly within the microcontroller’s internal EEPROM. Note: Note: 1. MAC addresses used for this package are Atmel property. The use of these MAC addresses for development purposes is permitted. Figure 3-3 shows a detailed description of the EEPROM data structure. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 6 Table 3-3. 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 ##.##.## 0x14 Feature uint8 Board features, coded into seven bits 7 Reserved 6 Reserved 5 External LNA 4 External PA 3 Reserved 2 Diversity 1 Antenna 0 SMA connector 0x15 Cal OSC 16MHz uint8 RF231 XTAL calibration value, register XTAL_TRIM 0x16 Cal RC 3.6V uint8 Atmel ATmega1281 internal RC oscillator calibration value @ 3.6V, register OSCCAL 0x17 Cal RC 2.0V uint8 Atmel ATmega1281 internal RC oscillator calibration value @ 2.0V, register OSCCAL 0x18 Antenna gain Int8 Antenna gain [resolution 1/10dBi]. For example, 15 will indicate a gain of 1.5dBi. The values 00h and FFh are per definition invalid. Zero or -0.1dBi has to be indicated as 01h or FEh 0x20 Board name char[30] Textual board description 0x3E CRC uint16 16-bit CRC checksum, standard ITU-T generator polynomial G16(x) = x16 + x12 + x5 + 1 Figure 3-3. Example EEPROM dump. -----| EEPROM dump |-------------0000 - 49 41 17 FF FF 25 04 00 D6 11 0010 - 02 04 01 01 06 02 A8 A9 01 FF 0020 - 52 61 64 69 6F 45 78 74 65 6E 0030 - 46 45 32 00 00 00 00 00 00 00 0040 - FF FF FF FF FF FF FF FF FF FF 0050 - FF FF FF FF FF FF FF FF FF FF 0060 - FF FF FF FF FF FF FF FF FF FF 0070 - FF FF FF FF FF FF FF FF FF FF ---------------------------------- 3.3 00 FF 64 00 FF FF FF FF 00 FF 65 00 FF FF FF FF 2A FF 72 00 FF FF FF FF 00 FF 32 00 FF FF FF FF 00 FF 33 8D FF FF FF FF 00 FF 31 9B FF FF FF FF IA...%......*... ................ RadioExtender231 FE2............. ................ ................ ................ ................ 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 3-4. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 7 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). This is required because the Atmel STK500 will provide 5V as default voltage, and the board can also be mounted with reverse polarity. Depending on the actual supply voltage, the diode D1 can consume several milliamperes. This has to be considered when the current consumption of the whole system is measured. In such a case, D1 should be removed from the board. To achieve the best RF performance, the analog (EVDD, AGND) and digital (DEVDD, DGND) supply are separated from each other by a CLC PI-element. Digital and analog ground planes are connected together on the bottom layer, underneath the radio transceiver IC. Further details are described in Chapter 4, page 10. All components connected to nets DEVDD/EVDD contribute to the total current consumption. Note: While in radio transceiver SLEEP state, most of the supply current is drawn by the 1MΩ pull-up resistor, R9, connected to the ID EEPROM and the EEPROM standby current. Figure 3-4. Power supply routing. CVTG F1 L1 JP1 MICROSMD035F DEVDD EVDD 220Ohm@100MHz X4 D1 BZG05C3V9 C18 4.7uF C30 100n C31 100n C26 4.7uF DGND DGND 3.4 DGND Radio transceiver reference clock The integrated radio transceiver is clocked by a 16MHz reference crystal. The 2.4GHz modulated signal is derived from this clock. Operating the node according to IEEE 802.15.4 [4], the reference frequency must not exceed a deviation of ±40ppm. The absolute frequency is mainly determined by the external load capacitance of the crystal, which depends on the crystal type and is given in its datasheet. The radio transceiver reference crystal, Q1, shall be isolated from fast switching digital signals and surrounded by a grounded guard trace to minimize disturbances of the oscillation. Detailed layout considerations can be found in Section 4.2. The REB uses a Siward CX4025 crystal with load capacitors of 10pF and 12pF. The imbalance between the load capacitors was chosen to be as close as possible to the desired resonance frequency with standard components. To compensate for fabrication and environment variations, the frequency can be further tuned using the radio transceiver register XOSC_CTRL (0x12) (refer to [1]). The REB production test guarantees a tolerance of within +20ppm and 5ppm. The correction value, to be applied to TRX register XOSC_CTRL (0x12), is stored in the onboard EEPROM (see Section 3.2). 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. The filter is designed to provide a stable 1MHz clock signal with correct logic level to a microcontroller pin with sufficiently suppressed harmonics. CLKM frequencies above 1MHz require a redesign of R8 and C36. In case of RC cut-off frequency adjustments, depending on the specific load and signal routing conditions, one may observe performance degradation of channel 26. Note: Channel 26 (2480MHz) is affected by the following harmonics: 155 × 16MHz or 310 × 8MHz. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 8 By default, CLKM is routed to a microcontroller timer input; check the individual configuration resistors in the schematic drawing. To connect CLKM to the microcontroller main clock input, assemble R3 with a 0Ω resistor. RF section The Atmel AT86RF231 radio transceiver incorporates all RF and BB critical components necessary to transmit and receive signals according to IEEE 802.15.4 or proprietary ISM data rates. To further improve system TX output power and RX sensitivity a FEM is connected to the radio transceiver. The Skyworks SE2431L FEM [9] is a high performance, fully integrated module in a 3 × 4 × 0.9mm³ 24 pin QFN package. It incorporates a transmit power amplifier (PA) with harmonic filtering, a receive low noise amplifier (LNA) with optional bypass switch, transmit/receive (TR) switching and an antenna diversity switch. A block diagram of the SE2431L is shown in Figure 3-5. ANT_SEL CTX CSD Figure 3-5. SE2431L block diagram. CPS 3.5 Logic control PA ANT1 TR ANT2 LNA SE2431L 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. There is provision on the PCB for C-L-C low pass filtering at the antenna ports to reduce harmonic levels at these higher output powers. In receive mode, conducted sensitivity is better than -104dBm for 1% packet error rate. The SE2431L has a typical receive noise figure of 2dB which includes all RF switch input losses. Referring to the Atmel REB231FE2 schematic in Appendix A.1, the RF interface consists of two antenna ports. By default two on-board ceramic antennas are connected allowing radiated measurements. Solder pads located along the tuning line allow for the optimization of antenna matching without the need for redesigning the PCB. Detailed information about the antenna diversity feature is given in [1] and [3]. Optionally two switched in-line MS-147 RF connectors, which disconnect the on-board antennas, allow conducted measurements. The SE2431L antenna ports are controlled by AT86RF231 pin DIG1 connected to SE2431L pin ANT_SEL. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 9 The SE2431L operating mode is determined by control lines CTX, CPS and CSD. The default configuration connects CPS pin to EVDD via R31. This means that in receive mode the LNA will always be enabled for maximum sensitivity. Enabling low power RX bypass mode requires removing R31 and R32 populated with 0R resistor. The PA is enabled when CTX is high and the LNA is enabled when CTX is low. When CSD, CTX and CPS pins are low, the SE2431L goes into low current standby mode (<1µA current consumption). CSD is connected to the AT86RF231 analog LDO regulator output (AVDD). AVDD is 1.8V for all AT86RF231 states except P_ON, SLEEP, RESET, and TRX_OFF. To enable/disable the SE2431L immediately and independently from individual radio transceiver states, an additional GPIO control line from the microcontroller is required. The SE2431L has two analog power supply pins, VCC1 and VCC2, which power the internal analog circuitry. This supply is connected to the REB231FE2 EVDD supply voltage. The interface between the AT86RF231 and the Skyworks SE2431L is single-ended 50Ω, optimized for high performance and low cost applications. The unused AT86RF231 RFN pin is terminated to ground with a 50Ω resistor and DC block. Avoiding a balun helps minimizing the bill of materials cost. In transmit mode, the AT86RF231 transmit output power needs to be set higher compared to a differential TRX-FEM interface using a balun. In receive mode, the effective gain ahead of the AT86RF231 is 3dB less than the specified SE2431L LNA gain (12.5dB). The resulting loss in sensitivity is about 0.3…0.4dB. Note: 4. The latest revision of SE2431L FEM [9] does not require resistor R30 connected to SE2431L pin 5, leave this pin unconnected as stated in the datasheet. 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. The PCB has to be considered as a part of the antenna; it interacts with the radiated electromagnetic wave • Around the SE2431L front end module layout, ensure good RF grounding, good thermal conduction, effective decoupling and correct microstrip impedances for RF tracks • • Isolate digital noise from the antenna and the radio transceiver to achieve optimum range and RF performance • Isolate digital noise from the 16MHz reference crystal to achieve optimum transmitter and receiver performance Reduce any kind of spurious emissions below the limits set by the individual regulatory organizations The Atmel REB231FE2 PCB design further demonstrates a low-cost, two-layer PCB solution without the need of an inner ground plane. The drawing in Figure 4-1 show critical sections using numbered captions. Each caption number has its own subsection below with detailed information. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 10 Figure 4-1. Board layout – RF section. 4.1 PCB detail 1 – balanced RF pin fan out Figure 4-2. 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. The solder paste mask has limited coverage for assembly purposes. The RF tracks to SE2431L TR, ANT1 and ANT2 pins, and tracking to the antennas, are all 50Ω microstrip. The 10pF decoupling capacitors C38 and C39 are placed close to the respective power supply pins. Grounded pins on the SE2431L are routed directly to the central ground pad. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 11 4.2 PCB detail 2 – crystal routing The reference crystal PCB area requires optimization to minimize external interference and to keep any radiation of 16MHz harmonics low. The reference crystal and load capacitors C34/35 form the resonator circuit. These capacitors are to be placed close to the crystal. The ground connection in between the capacitors should be the crystal housing contact, resulting in a compact, robust and stable resonator. The resonator block is enclosed within ground traces around it and a plane on the bottom side. Do not connect the resonator directly to the plane beneath the block. The only ground connection for the resonator block should be a trace in parallel with the two crystal lines that connects to TRX pin 27 or the paddle. Based on recent experiments, the bottom ground connection shall be routed directly to the paddle or pin 27. The loop is not required. In addition, the open space underneath the crystal can be filled with copper. A small keep out trace next to the bottom ground connection can help to keep this connection separate and prevent the layout tool from flooding across this trace. Figure 4-3. 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. 4.3 PCB – analog GND routing Analog ground pins (3, 6, 27, 30, 31 and 32) and pin 7 are to be routed to the paddle underneath the IC. The trace width has to be similar to the pad width when connecting the pads, and increase, if possible, some distance from the pad. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 12 Figure 4-4. Board layout – transceiver GND. 7 6 3 32 31 30 12 27 16 18 21 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. The soldering technology used allows the placement of small vias (0.15mm drill) within the ground paddle underneath the chip. During reflow soldering, the vias get filled with solder, having a positive effect on the connection cross section. The small drill size keeps solder losses within an acceptable limit. During the soldering process vias should be open on the bottom side to allow enclosed air to expand. 4.4 PCB – digital GND routing Digital ground pins (12, 16, 18 and 21) are not directly connected to the paddle. Digital ground pins may carry digital noise from I/O pad cells or other digital processing units within the chip. In case of a direct paddle connection, impedances of the paddle ground vias could cause a small voltage drop for this noise and may result in an increased noise level transferred to the analog domain. 4.5 PCB – GND plane Besides the function to provide supply ground to the individual parts, the ground plane has to be considered as a counterpart for the antenna. Such an antenna base plate is considered a continuous metal plane. For that reason, any unused surface should be filled with a copper plane and connected to the other ground side using sufficient through holes. Larger copper areas should also be connected to the other side layer with a grid of vias. This way, for an external electromagnetic field the board will behave like a coherent piece of metal. When a trace is cutting the plane on one side, the design should contain vias along this trace to bridge the interrupted ground on the other side. Place vias especially close to corners and necks to connect lose polygon ends. 4.6 Ceramic antenna design and tuning The antenna section follows an already existing similar implementation as described in Atmel AVR2043; REB231ED Radio Extender Board – Hardware User Manual; Rev. 8345A-AVR-05/11; Atmel Corporation. [10] application note. The application note provides detailed information about a design study, design-in and tuning. 3 Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 13 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 5-1. Mechanical outline. 57.00mm C C1 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 C39 C42 R31 R32 C38 R19 R29 R30 R6 C43 C27 L2 C41 C18 C34 JP1 1 Q1 D1 R2 F1 eg. ATmega 644 C30 R12 R22 R10 R20 R16 R26 R15 R25 R7 R17 R27 C35 U6 U4 R1 C37 R9 R3 R28 U3 R8 U5 1 R14 R24 R13 R23 C26 C31 1 L1 C33 C36 R11 R21 TP7 C28 63.00mm U1 TP6 TP5 C29 C32 TP4 TP3 TP2 TP1 R18 5. eg. ATmega 1281 40 X1 2 1 6.50mm Table 5-1. REB231FE2 mechanical dimensions. Dimension Value Width x 57mm Height y 63mm Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 14 6. Electrical characteristics 6.1 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. For more details about these parameters, refer to individual datasheets of the components used. Table 6-1. No. Parameter 7.1.1 Storage temperature range 7.1.2 Humidity 7.1.3 Supply voltage 7.1.4 EXT I/O pin voltage 7.1.5 Supply current from batteries 7.1.6 Note: 6.2 Condition 1. Minimum Typical Maximum Unit +85 °C 90 % r.H. -0.3 +3.6 V -0.3 VCC + 0.3 -40 Non-considerating Battery charge current Sum over all power pins -0.5 A (1) mA Keep power switch off or remove battery from REB-CBB when external power is supplied. Recommended operating range Table 6-2. No. Recommended operating range. Parameter Condition Minimum (1) 7.2.1 Operating temperature range Note -20 7.2.2 Supply voltage (VCC) REB231FE2 and REB-CBB 0.2 Note: 6.3 Absolute maximum rating. 1. Typical 3.0 Maximum Unit +70 °C 3.6 V Temperature range limited by crystal Q1, otherwise -40 … +85degC. Current consumption Test conditions (unless otherwise stated): VDD = 3.0V, fRF = 2.45GHz, TOP = 25°C, TX_PWR=0xA, X2 conducted Table 6-3 lists typical Atmel REB231FE2 current consumption values for different operating modes. Current measurement is taken by replacing REB231FE2 jumper ‘JP1’ with an amperemeter, for REB-CBB figures refer to [2]. Table 6-3. Current consumption of REB231FE2 (JP1). No. Parameter Condition 7.3.1 Supply current IDD,TRX_OFF CLKM off 0.44 7.3.2 Supply current IDD,PLL_ON SE2431L enabled, RX mode 10.8 7.3.3 Supply current IDD,RX_ON SE2431L LNA high gain 17.6 7.3.4 Supply current IDD,TX_Pmin BUSY_TX (+5dBm) 7.3.5 Supply current IDD,TX_Pdefault BUSY_TX (+20dBm) 7.3.6 Note: Supply current IDD,TX_Pmax 1. Minimum Typical Maximum Unit mA 40 (1) BUSY_TX (+23dBm) 116 205 VDD = 3.6V, AT86RF231 sub-register TX_PWR = 0x0. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 15 6.4 Transmitter characteristics Test conditions (unless otherwise stated): VDD = 3.0V, fRF = 2.45GHz, TOP = 25°C, TX_PWR=0xA, X2 conducted Table 6-4. No. Transmitter characteristics. Parameter Condition 7.4.1 TX Output Power 7.4.2 Output Power Range 7.4.3 Harmonics 7.4.4 Spurious Emissions Notes: Ch11 … 25, Ch26 (1) Minimum +5 average, worst case 4f0 Typical +20 Maximum (2) +23.5 Unit dBm 15 18 dB -50 -44 dBm/MHz tbd. dBm 1. Ch26 requires TX output power back-off and duty cycle operation, see Notes for details. 2. VDD = 3.6V, AT86RF231 sub-register TX_PWR = 0x0. Notes: 6.5 • The Atmel REB231FE2 setup has been tested for compliance with FCC and ETSI, see Appendix B. To ensure compliance, the following regional specific settings are to be ensured • FCC: Operating the transmitter at channel 26 requires limitation of TX output power to max. +13dBm and to ensure a duty cycle ≤25% • FCC: Operating the setup at maximum possible TX output power for all other channels requires either an adjustment of the lowpass filters (C25, L3, C40 and C27, L2, C41), or alignment of the TX duty cycle • ETSI: Operating the setup in Europe requires setting the Atmel AT86RF231 register TX_PWR to 0x0E maximum for all channels. This setting ensures compliance with ETSI EN 300 228 clause 4.3.2.2 Maximum Power Spectral Density (refer to [6]) Receiver characteristics Test conditions (unless otherwise stated): VDD = 3.0V, fRF = 2.45GHz , TOP = 25°C, X2 conducted Table 6-5. Receive characteristics. No. Parameter Condition 7.5.1 Receiver Sensitivity PER ≤1%, PSDU length 20 octets 7.5.2 Maximum RX input level -5(1) 7.5.3 Spurious Emissions -70 7.5.4 Notes: RSSI/ED offset (2)(3) SE2431L LNA in high gain mode Minimum Typical Maximum Unit -104 dBm 13 dB 1. Calculated, based on AT86RF231 maximum RX input level – SE2431L maximum RX gain. 2. AT86RF231 RSSI value indicates RF input power PRF[dBm] = (RSSI_BASE_VAL-13) + 3×(RSSI-1), see [1] in Chapter References. 3. AT86RF231 ED value indicates RF input power PRF[dBm] = -104 + ED, see [1] in Chapter References. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 16 7. Abbreviations AD - AES BB Antenna diversity - - Advanced encryption standard 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 - PCB PDI Power amplifier - - Printed Circuit Board Program/debug interface PER - Packet error rate R&TTE - Radio and Telecommunications Terminal Equipment (Directive of the European Union) REB - Radio extender board RF - RSSI Radio frequency - Received signal strength indicator RX - Receiver SPI - Serial peripheral interface TX - Transmitter XTAL - Crystal Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 17 S/N S/N1 1 DEVDD R2 nc SLPTR RSTN TP TP TP4 TP TP3 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 1001-121-002 RST 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 CVTG DGND PB6 PB4 PB2 PB0 PD6 PD4 PD2 PD0 EE#WP DGND PD0 PB0 PB2 PB3 PB1 PD6 PB4 PD4 PB5 1 6 1 5 U4B GND VCC 1 1 2 3 7 NC7WP32K8X_NL 5 6 4 8 2 3 SEL_TRX 74279263 Inductor_Iron U4A NC7WP32K8X_NL C30 100nF C18 4.7uF L1 0R00 R18 0R00 R17 0R00 R16 0R00 R15 0R00 R14 0R00 R13 0R00 R12 0R00 R11 0R00 R10 4 3 2 MISO EE#WP 1 DGND DGND 4.7uF C26 SEL_EE 100nF C31 EVDD IRQ SEL MOSI MISO SCK MCLK SLPTR DIG2 RSTN ATmega1281 config 1007-121-040 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 X1 DEVDD DGND DEVDD DGND Jumper X4 3 STK501 - EXPAND1 4 1M00 R9 SI SCK #HOLD AT25010B-MAHL-T GND #WP SO VCC AT25010B #CS U5 4 5 6 7 8 3.3p 0 Net Class i R31 1.5k 1.2k R19 R29 nc R32 0R00 DGND 100nF C37 DEVDD DGND EVDD DGND nc C13 nc 5 1uF C29 B1 B2 BOUT CTX CPS CSD ANT_SEL T/R Route DVSS pins to plane on top and not directly to the paddle underneath the IC R6 RSTN 49.9R DGND DNC DNC DNC DNC DNC GND GND GND GND GND GND VDD VCC1 VCC2 ANT2 DIG1 DIG2 SLP_TR DVSS DVDD DVDD DEVDD DVSS 2.2pF DGND MCLK R8 470R C36 22pF C43 3 4 7 8 17 9 10 11 12 14 18 5 22 19 13 15 AT86RF231-ZU AVSS U3 AVSS AT86RF231 AVSS AVDD EVDD AVSS XTAL1 XTAL2 6 AVSS DGND DGND Size: A3 Date: 7/5/2011 File: Title DGND EVDD 10pF 1 A C34 EVDD CSD TP7 TP6 DGND 10pF DGND DGND 1uF C33 DGND DIG4 DIG3 DGND 100nF EVDD C38 C42 EVDD MS-147 GND 7 nc nc Project: Revision: 1 Sheet 7 Q1 1 DGND 3 DGND 1uF C28 16MHz 1 of DGND 3.3p 8 FIDUCIAL 1.5mm FIDUCIAL 1.5mm mm 0 RF2 DGND A2 2.45GHz C2 Net Class i 8 RF1 LT08AD4303F ATMEL Automotive GmbH MCU Wireless 01099 Dresden Koenigsbruecker Landstrasse 61 Germany DGND 12pF C35 SH1 incl. A08-0961 PCB PCB1 5.5 C21 nc nc C22 DGND 10.3 9.5 8.7 7.9 7.1 6.3 Antenna Tuning Line Scale DGND C10 nc nc C20 DGND DGND C9 C7 C8 nc DGND DGND RadioExtender231FE2 32 31 30 29 28 27 26 25 33 DGND 10pF C39 R30 113k i Net Class C41 2.7nH L2 1.0pF DGND 2.7nH L3 i Net Class 22pF X3 GND C IN DGND 1.0pF DGND DGND C27 Net Class C12 i DGND 1.0pF C40 i Net Class Net Class i ANT1 DGND 9 10 11 12 13 14 15 16 22pF Net Class C25 i C11 6 DGND DGND 1.0pF C DGND SE2431L-R DGND DIG1 DIG2 SLPTR 2 1 23 24 21 20 16 6 U1 MS-147 GND IN X2 GND DGND DGND DGND 1uF C32 TP A C15 nc TP5 DIG3 CSD DIG1 DEVDD DGND nc C5 nc nc C14 DGND DGND mm 5.5 6.3 7.1 7.9 8.7 9.5 10.3 Antenna Tuning Line Scale C3 nc C6 DGND C4 DGND DGND MOSI SCK A1 2.45GHz C1 5 2 RSTN SEL DGND CVTG PD2 PB4 PB5 PB6 PB7 PB1 PD7 PD6 PB2 ATmega644 config R1 nc MCLK DGND 2 1 4 D C B A To make use of BOD, assemble resistors with 1M0 to avoid radio wake up in case of a BOD reset condition. 2 Paddle (GND) 25 1 8 7 6 5 4 3 2 1 1 SCK MISO 2 1 RST TST AVSS RFN RFP AVSS DIG4 DIG3 1 CLKM DVSS SCLK MISO DVSS MOSI SEL IRQ 2 17 18 19 20 21 22 23 24 D C B A A.1 MOSI SEL_TRX IRQ Appendix A. PCB design data Schematic Figure 7-1. Atmel REB231FE2 schematic. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 18 Assembly drawing Figure 7-2. 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 C27 L2 C41 TP6 L1 R9 D1 F1 eg. ATmega 644 C30 R12 R22 R10 R20 R16 R26 R15 R25 R7 R17 R27 JP1 U6 U4 R2 R3 Q1 1 U5 1 R14 R24 R13 R23 R28 R11 R21 R8 R1 C37 C36 C34 C33 U3 C35 C18 TP5 C29 C32 40 TP7 C28 C26 C31 U1 1 C39 C42 R31 R32 C38 R19 R29 R30 R6 C43 TP4 TP3 TP2 TP1 R18 7.2 eg. ATmega 1281 X1 2 1 Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 19 A.2 Bill of materials Table 7-1. Qty. Bill of materials. 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 2.4GHz radio transceiver MLF-32 AT86RF231 Atmel AT86RF231 1 U6 Dual INV, ULP SC-70/6 NC7WV04P6X Fairchild NC7WV04 1 U1 RFFE QFN24 SE2431L Skyworks SE2431L 9 R10, R11, R12, R13, R14, R15, R16, R17, R18 Resistor 0603H0.4 Generic 0Ω 1 R31 Resistor 0402 Generic 0Ω 1 R8 Resistor 0402A Generic 470Ω 2 R7, R9 Resistor 0402A Generic 1MΩ 1 R19 Resistor 0402A Generic 1.5kΩ 1 R29 Resistor 0402A Generic 1.2kΩ 1 R30 Resistor 0402A Generic 113kΩ 1 R6 Resistor 0201A Generic 49.9Ω 1 Q1 Crystal 16MHz XTAL_4X2_5_ small XTL551150NLE16MHz-9.0R Siward CX-4025 16MHz 1 L1 SMT ferrite bead 0603H0.8 74279263 Würth 220Ω@100MHz 2 L2, L3 Chip Inductor 0402 (32306) L0075S0083LQG15 HN Murata ±0.3nH 1 JP1 Jumper 2-pol. JP_2x1 1001-121-002 CAB JP-2 1 F1 PTC fuse 1210 MICROSMD035F Tyco MICROSMD035F 1 D1 Z-Diode DO-214AC BZG05C3V9 Vishay BZG05C3V9 1 C35 Capacitor 0402A Generic C0G 12pF/5% 3 C34, C38, C39 Capacitor 0402A Generic C0G 10pF/5% 4 C28, C29, C32, C33 Capacitor 0603H0.8 Generic X5R 1µF 4 C30, C31, C37, C42 Capacitor 0402A Generic X7R 100n 3 C11, C12, C43 Capacitor 0402A Generic C0G 22pF 1 C36 Capacitor 0402A Generic C0G 2.2pF 2 C1, C2 Capacitor 0402A Generic C0G 3.3pF 2 C18, C26 Capacitor 0603A GRM1555C1H1R0 CA01 Generic X5R 4.7µF 4 C25, C27, C40, C41 Capacitor 0402A 2450AT45A100 Murata 1.0pF ±0.25pF 2 A1, A2 Ceramic antenna ANT_AT45_45 deg Johanson 2.45GHz Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 20 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. To fulfill FCC Certification requirements, an Original Equipment Manufacturer (OEM) must comply with the following regulations: • The modular transmitter must be labeled with its own FCC ID number, and, if the FCC ID is not visible when the module is installed inside another device, then the outside of the device into which the module is installed must also display a label referring to the enclosed module • This exterior label can use wording such as the following. Any similar wording that expresses the same meaning may be used Contains FCC-ID: VNR-E31F2-X5B-00 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. Use in portable exposure conditions (FCC 2.1093) requires separate equipment authorization. Modifications not expressly approved by this company could void the user's authority to operate this equipment (FCC Section 15.21). Compliance 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 or more 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 Warning (Part 15.21) Changes or modifications not expressly approved by this company could void the user’s authority to operate the equipment. 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. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 21 The manufacturer must maintain a copy of the device documentation and ensure the final product does not exceed the specified power ratings, and/or installation requirements as specified in the user manual. If any of these specifications are exceeded in the final product, a submission must be made to a notified body for compliance testing to all required standards. The “CE“ marking must be affixed to a visible location on the OEM product. The CE mark shall consist of the initials "CE" taking the following form: • If the CE marking is reduced or enlarged, the proportions given in the above graduated drawing must be respected • The CE marking must have a height of at least 5mm except where this is not possible on account of the nature of the apparatus • The CE marking must be affixed visibly, legibly, and indelibly More detailed information about CE marking requirements you can find at "DIRECTIVE 1999/5/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL" on 9 March 1999 at Section 12. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 22 Appendix C. 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-AVR05/11; Atmel Corporation. [3] AVR2021: AT86RF231 Antenna Diversity; Application Note; Rev. 8158B-AVR-07/08; Atmel Corporation. [4] IEEE Std 802.15.4™-2006: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs). [5] FCC Code of Federal Register (CFR); Part 47; Section 15.35, Section 15.205, Section 15.209, Section 15.231, Section 15.247, and Section 15.249. United States. [6] ETSI EN 300 328, Electromagnetic Compatibility and Radio Spectrum Matters (ERM); Wideband Transmission Systems; Data transmission equipment operating in the 2.4GHz ISM band and using spread spectrum modulation techniques; Part 1-3. [7] ARIB STD-T66, Second Generation Low Power Data Communication System/Wireless LAN System 2003.03.26 (H11.12.14) Version 2.1. [8] AT25010B: SPI Serial EEPROM; Datasheet; Rev. 8707C-SEEPR-6/11; Atmel Corporation. [9] SE2431L: 2.4GHz ZigBee/802.15.4 Front End Module; SiGe Semiconductor; Datasheet; Rev 1.8; Aug-082010; Skyworks Solutions, Inc. [10] Atmel AVR2043; REB231ED Radio Extender Board – Hardware User Manual; Rev. 8345A-AVR-05/11; Atmel Corporation. Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 23 Appendix D. Revision history Version Description A08-1170/1 Initial release Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 24 Appendix E. 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). Atmel supplied this board/kit “AS IS,” without any warranties, with all faults, at the buyer’s and further users’ sole risk. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user indemnifies Atmel from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge and any other technical or legal concerns. EXCEPT TO THE EXTENT OF THE INDEMNITY SET FORTH ABOVE, NEITHER USER NOR ATMEL SHALL BE LIABLE TO EACH OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. No license is granted under any patent right or other intellectual property right of Atmel covering or relating to any machine, process, or combination in which such Atmel products or services might be or are used. Mailing Address: Atmel Corporation, 2325 Orchard Parkway, San Jose, CA 95131 Copyright © 2012, Atmel Corporation Atmel AVR2080: REB231FE2 – Hardware User’s Manual [APPLICATION NOTE] 8479B−AVR−07/2012 25 Atmel Corporation Atmel Asia Limited Atmel Munich GmbH Atmel Japan G.K. 1600 Technology Drive Unit 01-5 & 16, 19F Business Campus 16F Shin-Osaki Kangyo Bldg. San Jose, CA 95110 BEA Tower, Millennium City 5 Parkring 4 1-6-4 Osaki, Shinagawa-ku USA 418 Kwun Tong Road D-85748 Garching b. Munich Tokyo 141-0032 Tel: (+1)(408) 441-0311 Kwun Tong, Kowloon GERMANY JAPAN Fax: (+1)(408) 487-2600 HONG KONG Tel: (+49) 89-31970-0 Tel: (+81)(3) 6417-0300 www.atmel.com Tel: (+852) 2245-6100 Fax: (+49) 89-3194621 Fax: (+81)(3) 6417-0370 Fax: (+852) 2722-1369 © 2012 Atmel Corporation. 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