dresden elektronik ingenieurtechnik 23SXX 2.4GHz IEEE 802.15.4 compliant radio module User Manual deRFsamR21E 23S00 23S20

dresden elektronik ingenieurtechnik gmbh 2.4GHz IEEE 802.15.4 compliant radio module deRFsamR21E 23S00 23S20

User man

deRFsamR21E -23S00/-23S20 Datasheet 1. General description The deRFsamR21E is a 2.4GHz ZigBee 3.0 radio module series which integrates the SoC ATSAMR21E18 from Microchip / Atmel together with a 4 Mbit data flash on a tiny size of 21 mm x 13 mm. The microcontroller ATSAMR21E18 integrates a powerful and energy efficient 32-Bit ARM Cortex-M0+ core together with a 2.4 GHz ZigBee radio transceiver. The module comes with 16 I/O’s, 256 kbit internal program flash and 4 Mbit data flash for firmware updates over the air and data storage. For reliable assembly the module offers SMD solderable side contacts in 50 mil / 1.27 mm grid. The module offers ZigBee 3.0 support for smart devices. Two radio module variants are available:  deRFsamR21E-23S00: integrated RF-design with chip antenna  deRFsamR21E-23S20: coaxial u.FL-connector for external antenna applications as well as a RF-pad for custom RF-designs e.g. external frontend or antenna diversity deRFsamR21E-23S00 deRFsamR21E-23S20 2. Features  ATSAMR21E18 Single-chip ARM Cortex-M0+ based 32-bit Microcontroller with Low Power 2.4 GHz Transceiver for IEEE 802.15.4 and ZigBee Applications with 256 KB Flash and 16 I/O’s - all accessible outside the module (four occupied by data flash) - Maximum operating frequency 48 MHz - 128-bit AES crypto engine - 32-bit MAC symbol counter - Temperature sensor - Automatic transmission modes  4 Mbit data flash for firmware updates over the air and data storage  Ready-to-use RF design  Radio module with a link budget of up to 103 dBm  CE compliant according to RED 2014/53/EU and FCC certified  Single 2.5 V - 3.6 V supply  Industrial temperature range -40°C to 85°C  1.27 mm / 50 mil pin header with several alternative functions: - Analog input (12-bit, 350ksps Analog-to-Digital Converter) - PWM output - TWI (I2C up to 3.4MHz) - SPI - UART - USB - GPIO - SWD programming interface  High precision 16 MHz crystal oscillator
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 2 of 36 Table of contents 1. General description ......................................................................................................... 1 2. Features .......................................................................................................................... 1 1. Overview ......................................................................................................................... 6 2. Applications ..................................................................................................................... 6 3. Block diagram .................................................................................................................. 7 4. Pinout .............................................................................................................................. 9 5. Mechanical description .................................................................................................. 10 5.1. Module dimensions............................................................................................... 10 5.2. Recommended footprint ....................................................................................... 11 5.3. ECAD libraries ...................................................................................................... 12 5.4. STEP model library............................................................................................... 12 6. Electrical specification ................................................................................................... 13 6.1. Absolute Maximum Ratings .................................................................................. 13 6.2. Electrical Characteristics ...................................................................................... 13 6.3. TX Power register settings .................................................................................... 14 6.4. Fuse setting .......................................................................................................... 15 7. Onboard SPI Serial Flash .............................................................................................. 16 7.1. Commands ........................................................................................................... 16 7.2. Status register ...................................................................................................... 17 7.3. Flash Timings ....................................................................................................... 17 8. Recommended configuration ......................................................................................... 18 8.1. Signal description ................................................................................................. 19 8.2. UART ................................................................................................................... 19 8.3. I2C (TWI) .............................................................................................................. 20 8.4. USB ...................................................................................................................... 20 8.5. SPI ....................................................................................................................... 20 8.6. ADC ..................................................................................................................... 20 8.7. SWD ..................................................................................................................... 20 8.8. GPIO .................................................................................................................... 20 8.9. Reset .................................................................................................................... 20 9. Application Information .................................................................................................. 21 9.1. PCB Technology .................................................................................................. 21 9.2. Power supply ........................................................................................................ 21 9.3. Ground plane........................................................................................................ 21 9.4. Layers .................................................................................................................. 21 9.5. Traces below the module...................................................................................... 22 9.6. Placement on the PCB ......................................................................................... 22 9.7. Recommended layout for deRFsamR21E-23S00 ................................................. 23 9.8. RF Design for deRFsamR21E-23S20 ................................................................... 24 9.8.1. External front end and antenna diversity ................................................... 24
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 3 of 36 10. Programming ................................................................................................................. 26 10.1. Software/Applications ........................................................................................... 26 10.2. Clocks .................................................................................................................. 26 10.3. Pre-flashed firmware ............................................................................................ 27 11. Radio certification .......................................................................................................... 28 11.1. United States (FCC) ............................................................................................. 28 11.2. European Union (ETSI) ........................................................................................ 29 11.3. Approved antennas .............................................................................................. 30 12. Ordering information ...................................................................................................... 31 13. Packaging dimension .................................................................................................... 32 14. Soldering profile............................................................................................................. 33 15. Revision notes ............................................................................................................... 34 16. References .................................................................................................................... 35
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 4 of 36 Document history Date Version Description 2017-09-13 0.9 Preliminary version
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 5 of 36 Abbreviations Abbreviation Description IEEE 802.15.4 Communication standard, applicable to low-rate Wireless Personal Area Networks (WPAN) 6LoWPAN IPv6 over Low Power Wireless Personal Area Networks ADC Analog to Digital Converter ASF Atmel Software Framework EMI Electromagnetic Interference ETSI European Telecommunications Standards Institute FCC Federal Communications Commission GPIO Generals Purpose Input Output LNA Low Noise Amplifier MAC Medium (Media) Access Control MCU, µC Microcontroller Unit OTAU Over the air update PA Power Amplifier PCB Printed Circuit Board PWM Pulse Width Modulation RED Radio Equipment Directive RF Radio Frequency R&TTE Radio and Telecommunications Terminal Equipment (Directive of the European Union) SoC System On Chip SPI Serial Peripheral Interface SWD Serial Wire Debug TWI Two-Wire Serial Interface U[S]ART Universal [Synchronous/]Asynchronous Receiver Transmitter USB Universal Serial Bus ZigBee Low-cost, low-power wireless mesh network standard. The ZigBee Alliance is a group of companies that maintain and publish the ZigBee standard.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 6 of 36 1. Overview The deRFsamR21E series is the second generation of small, ready-to-use radio modules that provides a fully integrated solution for wireless applications, using the IEEE802.15.4 standard in the 2.45 GHz ISM frequency band. All required RF components are already integrated on the module, therefore no expensive RF design is needed. Features can be added by simply connect-ing sensors and output stages to the module. The deRFsamR21E module series reduces time to market, effort and cost significantly for wireless applications. The deRFsamR21E series is based on the SoC ATSAMR21E18 from Microchip/ Atmel which features an ARM Cortex-M0+ core and a 2.4 GHz ZigBee transceiver. It enables use of ZigBee 3.0 for smart devices in a wide field of applications. For this tiny series, dresden elektronik is us-ing a footprint, which offers SMD solderable side contacts in a 50 mil / 1.27 mm grid for easy assembly and inspection. The module offers 256 KB internal flash as program memory as well as 4 Mbit data flash for firmware updates over the air and data storage. Two radio module variants are available:  deRFsamR21E-23S00: integrated RF-design with chip antenna for easy and fast integration with no need for custom RF design and low BOM cost since all necessary components are integrated on the module  deRFsamR21E-23S20: coaxial u.FL-connector for external antenna applications as well as a RF-pad which enables custom RF-design e.g. use of external frontend with power amplifier/ low noise amplifier or antenna diversity Both modules are full compliant to all EU and FCC regulatory requirements. 2. Applications The main applications for the radio modules are:  ZigBee 3.0  Smart Home  Lighting Application  Home Automation  Wireless Sensor Networks  Industrial Controlling  Smart Metering  6LoWPAN
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 7 of 36 3. Block diagram Figure 5-15 shows the block diagram of the radio module deRFsamR21E-23S00. ATSAMR21E184Mbit Serial Flash Balun & Harmonic FilterChipAntennaSPI12 GPIOSPIVCC Figure 3-1: Block diagram deRFsamR21E-23S00 Figure 5-2 shows the block diagram of the radio module deRFsamR21E-23S20 with u.FL connector. ATSAMR21E18 Balun & Harmonic Filter12 GPIOU.FL4Mbit Serial Flash SPISPIVCC Figure 5-2: Block diagram deRFsamR21E-23S20
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 8 of 36 Figure 5-3 shows the block diagram of the radio module deRFsamR21E-23S20 with RF-out pad. ATSAMR21E18 Balun & Harmonic Filter12 GPIO4Mbit Serial Flash SPISPIVCCRF-out Figure 5-3: Block diagram deRFsamR21E-23S20 with RF-out pad used
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 9 of 36 4. Pinout In this chapter the pinout is described. The following figure shows the pinout of the radio module. The pinout applies to both variants 23S00 and 23S20. Top-View 1 GND 2 NC/RF-OUT1 3 GND 4 GND 27 GND 5 PA14 26 PA09 6 PA15 25 PA08 7 PA16/MISO2 24 PA06 8 PA17/CLK2 23 PA07 9 PA18/SS2 22 GND 10 PA19/MOSI2 21 RESET 11 PA24 20 PA31 12 PA25 19 PA30 13 VCC 18 PA28 14 VCC 17 PA27 15 GND 16 GND 1. RF-OUT only for deRFsamR21E-23S20, do not connect for deRFsamR21E-23S00 and if unused. 2. The onboard data flash is connected to the controller at these pins. The SPI chip-select (SS signal) is not available for use other than internal data flash control. For a recommended configuration of the module pins with all common interfaces see Section 10. A more detailed description on port to function assignment can be found in [1] Table 5-1.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 10 of 36 5. Mechanical description 5.1. Module dimensions The mechanical dimensions are described in this chapter. The modules size is 21.0 x 13.0 x 2.5 mm (0,827 x 0,512 x 0,098 inch). Figure 7-1 shows additional dimensions. Figure 7-1: mechanical dimensions of the module
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 11 of 36 5.2. Recommended footprint Both radio module types share the same footprint, only the area which it is not allowed to place copper on is different. Figure 7-2: Recommended Footprint for deRFsamR21E-23S00
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 12 of 36 Figure 7-3: Recommended Footprint for deRFsamR21E-23S20 The recommended  pad size is 0.9 x 1.4 mm,  solder mask clearance is 75 to 100 µm,  stencil opening is 0.8 x 1.25 mm with stencil thickness 100 to 150 µm. The 23S00 with internal antenna requires the user to follow the placement and layout guidelines for best RF performance. For more details see Section 11.6 and 11.7. With the RF-pad of 23S20 it is possible to implement antenna diversity and front-end design for increased transmit power and receiver sensitivity as well as custom antenna design. More details can be found in chapter 11.8.1 External front end and antenna diversity. 5.3. ECAD libraries dresden elektronik offers schematic and footprint libraries for all available radio modules for ECAD design software Altium Designer® [3] and Eagle® [5]. This allows a fast design-in of radio modules into a custom product. The pin-assignment in the schematic library is a suggestion for frequently used functions. A detailed description on this configuration can be found in Section 10. The pins can be muxed in many different ways with other functions depending on application needs. For more details on that refer to Section 6. 5.4. STEP model library dresden elektronik offers a STEP model library with all available OEM radio modules for CAD design tools [7].
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 13 of 36 6. Electrical specification This section will outline the main parameters required to build applications. The module characteristics are determined by the implemented parts. See references at the end of this document for required datasheet references. 6.1. Absolute Maximum Ratings Stresses beyond those listed in Table 8-1 may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or other conditions beyond those indicated in the operational sections of this specification are not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 8-1: Absolute maximum ratings Symbol Parameter Condition Min Typ Max Unit TOP Operating temperature -40 +85 °C Tstorage Storage temperature -40 +125 °C VPIN Pin voltage with respect to GND and VCC GND -0.3 VCC +0.3 V VCC Maximum VCC pin voltage 0 3.8 V VESD ESD robustness Human Body Model Charged Device Model 4 550 kV V PRF Input RF level +10 dBm 6.2. Electrical Characteristics The data in the following table is measured at a temperature of 25°C with supply voltage of 3.3 V if not otherwise noted. Table 8-2: Electrical specification data Symbol Parameter Condition Min Typ Max Unit VCC Power supply voltage Default Mode for full operation of data flash 2.5 3.3 3.6 V For USB interface 3.0 3.3 3.6 V IDDOTAU Current consumption OTAU transceiver in RXON state and data flash write TBD mA IDD1 Current consumption of parts (data flash in standby mode) MCU running while(1) loop 3.4 mA Transceiver in RXON state 11.8 mA Transceiver in TXON state 13.8 mA IDD2 Current consumption MCU and data flash in deep power down 5 22 µA IDD3 Current consumption (data flash only) Read 4 12 mA Page Program 10 20 PRF RF transmit power conducted 4 dBm
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 14 of 36 PRange Output power range 16 steps configurable transceiver output power -17 4 dB Pemit RF transmit power radiated deRFsamR21E-23S00 (chip antenna)2 4 dBm EIRP radiated deRFsamR21E-23S20 using antenna Wimo 17013 (+5 dBi) 9 dBm EIRP Dlos Maximum line of sight range3 deRFsamR21E-23S00 (chip antenna) 200 m deRFsamR21E-23S20 (2 dBi Gain antenna) 220 m RXsens Receiver sensitivity Data Rate 250 kBit/s Data Rate 500 kBit/s Data Rate 1 MBit/s Data Rate 2 MBit/s -99 -94 -92 -86 dBm dBm dBm dBm PSPUR_TX Transmitter spurious emissions according to EN 300328 V2.1.1 (as measured in certification tests) 30 MHz to 1 GHz -62 dBm 1 GHz to 4 GHz -38 dBm 4 GHz to 12.75 GHz -58 dBm ESPUR_TX Transmitter spurious emissions according to FCC 15.247 (as measured in certification tests) 30 MHz to 200 MHz 35 dBµV/m 200 MHz to 1 GHz 22 dBµV/m 1 GHz to 4 GHz 36 dBµV/m 4 GHz to 26.5 GHz 48 dBµV/m 2.3 GHz to 2.4 GHz 53 dBµV/m 2.484 GHz to 2.5 GHz 61 dBµV/m fCPU Maximum MCU clock 48 MHz fTRXosc Transceiver oscillator frequency 16 MHz fTRXoscdev Transceiver oscillator frequency deviation At 25°C -10 +10 ppm -40°C < TOP < +85°C -20 +20 ppm Note: 1. For FCC band edge compliance with deRFsamR21E-23S20 it is required to operate Ch26 with not more than TX_PWR=0x7 (0 dBm). 2. Based on RF pattern measurement with USB powered Baseboard 3. Measured at height of 1.5 m above flat land of grass with transmit power 4 dBm. 6.3. TX Power register settings The output power of the transceiver can be configured with the TX_PWR register according to Table 8-3.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 15 of 36 Table 8-3: TX_PWR Register settings at 3.0V TX_PWR Value TX Output Power [dBm] Current Consuption [mA]1 0x0 4 13.8 0x1 3.7 0x2 3.4 0x3 3 0x4 2.5 0x5 2 0x6 1 0x7 0 11.8 0x8 -1 0x9 -2 0xA -3 0xB -4 0xC -6 0xD -8 0xE -12 0xF -17 7.2 Note: 1. Current consumption for transceiver only, MCU and data flash currents have to be considered as well 6.4. Fuse setting Fuses are used to configure the ATSAMR21E18 operation modes and clocks. This is mainly done by internal commands which can be found in [1].
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 16 of 36 7. Onboard SPI Serial Flash The module incorporates a 4 MBit data flash connected to the module by SPI bus. The data flash connects to PA16-PA19 according to Table 9-1. Table 9-1: Dataflash to microcontroller connection Port Function Flash pin Controller settings PA16 MISO SO PA16 SERCOM1 or 3 PAD[0] DIPO=0x0 PA17 SCK SCK PA17 SERCOM1 or 3 PAD[1] DOPO=0x2 PA18 GPIO SS PA18 to be set low in software before SPI access PA19 MOSI SI PA19 SERCOM1 or 3 PAD[3] DOPO=0x2 The signals in this table are available at module pins 7-10 as well. The module contains the serial data flash AT25SF041 according to Table 9-2. Since the memory market is very difficult at the moment, the module incorporates some alternative flash devices listed in Table 9-3. This is done to avoid supply bottlenecks. To avoid problems, no specific flash ID shall be used in the customer firmware. This section outlines basic usage instructions. For a more detailed description refer to the datasheets of the flash devices. Table 9-2: default serial data flash Partnumber Manufacturer JEDEC ID (9Fh) Datasheet reference AT25SF041 Adesto 1F-84-01 [9] Table 9-3: second source serial data flash list Partnumber Manufacturer JEDEC ID (9Fh) Datasheet reference MX25V4006E Macronix C2-20-13 [10] W25X40CL Winbond EF-30-13 [11] W25Q40CL Winbond EF-40-13 [12] 7.1. Commands To ease the implementation of the different flash devices Table 9-4 lists the commands and their respective opcodes common to all the flash devices listed above. Table 9-4: command table common to all flash options Command Opcode Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte n Write enable 06h Write disable 04h Read Status Register 05h (S7-S0) Write Status Register 01h S7-S0 see* Page Program 02h A23-A16 A15-A8 A7-A0 (D7-D0) (next byte) Up to 256 bytes Sector Erase (4kB) 20h A23-A16 A15-A8 A7-A0 Block Erase (64kB) D8h A23-A16 A15-A8 A7-A0 Chip Erase C7h/60h Power-down B9h Resume from Deep Power Down ABh Resume from Deep Power Down and read ID ABh dummy dummy dummy (IRD7-IRD0)
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 17 of 36 Read Data (up to 30 MHz) 03h A23-A16 A15-A8 A7-A0 (D7-D0) (next byte) continuous Fast Read (up to 70 MHz) 0Bh A23-A16 A15-A8 A7-A0 dummy (D7-D0) continuous Read Manufacturer and Device ID 9Fh (M7-M0) (ID15-ID8) (ID7-ID0) Read ID 90h dummy dummy 00h (M7-M0) (IRD7-IRD0) *make sure not to send a second byte since it may lead to locked and not resettable protection with some of the flash devices 7.2. Status register The status register is described in Table 9-5. Table 9-5: flash status register Bit content explanation Type S7 SRP Software Protected R/W S6 0 Do not use (always set to 0) R/W S5 0 Do not use (always set to 0) R/W S4 BP2 Block Protection Bit 2 R/W S3 BP1 Block Protection Bit 1 R/W S2 BP0 Block Protection Bit 0 R/W S1 WEL Write Enable Latch status R S0 BUSY Indicates ready/busy status R Status register bit S5 and S6 always have to be programmed to 0 to ensure proper operation of the block protection according to Table 9-6. While reading ignore S5 and S6. Table 9-6: block protection BP2 BP1 BP0 Address Range Portion 0 0 0 None None 0 0 1 070000h-07FFFFh Upper 1/8 0 1 0 060000h-07FFFFh Upper 1/4 0 1 1 040000h-07FFFFh Upper 1/2 1 X X 000000h-07FFFFh All 7.3. Flash Timings Table 9-7 contains typical and maximum values for timings. Typical values refer to the standard flash AT25SF041 while maximum values apply to all the listed flash devices. Table 9-7: timings of onboard flash Parameter Typ Max Unit Page Program 0.7 2.5 ms Byte Program 5 us Block erase 4K 60 300 ms Block erase 64K 500 2200 ms Chip Erase 4 10 s tCSS 7 ns tV Output Valid time 8 ns
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 18 of 36 8. Recommended configuration This chapter describes a recommended configuration which enables use of all frequently used interfaces. The schematic symbol used in this chapter as well as a footprint can be found in dresden elektronik Altium and Eagle libraries (see Section 7.3). Figure 10-1 shows the schematic of a sample application. The sample application provides USB and incorporates two sensors, a LED, an analogue input measuring the battery voltage and using the UART interface through a 6-pin header for tracing. This configuration with all common interfaces is shown in Figure 10-1. Figure 10-1 configuration with all common interfaces
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 19 of 36 8.1. Signal description The features of the controller can be mapped to different ports. How to configure the device for the example configuration is described in this chapter. The serial interface functions are organized in SERCOM units (Serial Communication Interface). These units consist of 4 Signals and can be mapped to several ports of the microcontroller. The configuration is shown in Table 10-1. Table 10-1: Pin configuration Pin Pad Function Config 05 PA14 UART/TXD SERCOM2/PAD2 06 PA15 UART/RXD SERCOM2/PAD3 07 PA16 SPI_MISO SERCOM1/PAD0 08 PA17 SPI_MOSI SERCOM1/PAD1 09 PA18 SPI_SS Digital out 10 PA19 SPI_CLK SERCOM1/PAD3 11 PA24 USBDM 12 PA25 USBDP 17 PA27 GPIO Digital out 18 PA28 SPI_SS2 Digital out 19 PA30 SWD/SWCLK 20 PA31 SWD/SWDIO 21 - RESET 23 PA07 ADC/AIN7 24 PA06 ADC/AIN6 25 PA08 I2C/SDA SERCOM0/PAD0 26 PA09 I2C/SCL SERCOM0/PAD1 8.2. UART The UART interface is a commonly used bidirectional interface for communication between microcontrollers. The transmit (TXD) and receive (RXD) lines have to be connected directly to the second device. TXD for the host controller is RXD for the client, the other signal works accordingly. For communication to a host with a different supply voltage domain it is necessary to use a level-shifter part. We recommend the USB level shifter by dresden elektronik. The level-shifter can be connected to the custom base board via 100 mil 2 x 3 pin header. The pin assignment should be designed as below in Figure 10-2. For a UART connection it is sufficient to use only TXD, RXD and GROUND signals. 1. PA14/TXD 2. VCC 3. Not connected 4. PA15/RXD 5. Not connected 6. GND Figure 10-2: 100 mil / 2,54 mm 2 x 3 pin header for UART
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 20 of 36 8.3. I2C (TWI) The I2C (Inter-Integrated Circuit, also referred to as TWI – two wire interface) is a common interface for sensor connection and it is able to connect several devices at one bus. There is one clock signal (SCL) and a data signal (SDA). It is necessary to place pull-up resistors for both lines externally to the radio module for proper function. We recommend the use of 4.7 kΩ resistors as shown in Figure 10-3. Figure 10-3: Two Wire Interface 8.4. USB The USB (Universal Serial Bus) interface complies with USB 2.1 specification. It supports both device and embedded host modes. PA24 (USBDM) and PA25 (USBDP) are routed as differential lines from the MCU to the radio module side contacts to pins 11 and 12. The module power supply cannot be operated directly from a 5 V USB source. The module base board has to implement the required voltage regulator for recommended voltage supply of 3.3 V. For USB operation a minimum supply voltage of 3.0 V is required. 8.5. SPI The SPI (Serial Peripheral Interface) is a synchronous serial communication interface commonly used in embedded systems. The SPI Interface on this module is used by the onboard serial data flash. To add another device to the SPI Bus SCLK, MISO and MOSI can be used, only another chip select signal (SS) is needed for each device. Any GPIO can be used for this purpose, except pin 9 (PA18) since it is connected to the chip select of the onboard data flash. In this example pin 18 (PA28) is used for the SPI Sensor chip select. 8.6. ADC The module contains an ADC (Analog to Digital Converter) with 12-bit resolution. It supports sample rates up to 350 ksps. Pin 23 and 24 (PA07 and PA06) are used in this configuration. The internal reference voltage can be set to 1.0 V, VCC/1.48 and VCC/2. 8.7. SWD The SWD interface consists of clock signal (SWCLK) and data signal (SWDIO) as well as the RESET signal for programming and debugging the microcontroller. More details on programming can be found in Section 12. 8.8. GPIO In this example pin 17 (PA27) and pin 18 (PA28) are reserved for GPIO usage, but nearly every pin can be used as GPIO if not used otherwise. 8.9. Reset The reset pin is low active and has an internal 10k pull-up resistor to power supply VCC.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 21 of 36 9. Application Information The PCB design of a radio module base board is important for a proper performance of peripherals and the radio. The next subsections give design hints to create a custom base board. 9.1. PCB Technology The module is designed for use with standard PCB technology to reduce the costs and cover a wide application range. 9.2. Power supply Power supply pins 13 and 14 have to be connected to a power domain of 2.5 to 3.6 V. No external decoupling components are needed. For noisy environments it is recommended to include a filter consisting of a ferrite or inductor and capacitors to reduce noise on the power domain to the module. An example is shown in Figure 11-1. Place all components in near proximity to each other and C2 between Pin 14 and 15 next to the module. Figure 11-1: Power supply decoupling for noisy environments 9.3. Ground plane The performance of RF applications mainly depends on the ground plane design. The often used chip ceramic antennas are very tiny, but they need a proper ground plane to establish a good radiation pattern. Every board design is different and cannot easily be compared to each other. Some practical notes for the ground plane design are described below:  Regard to the design guideline of the antenna manufacturer  Use closed ground planes on the PCB edges on top and bottom layer  Connect the ground planes with lots of vias. Place it inside the PCB like a chessboard and on the edges very closely. 9.4. Layers The use of 2 or 4 layer PCB boards have advantages and disadvantages for the design of a custom base board. Table 11-1: 2 and 4 layer board properties in comparison 2 Layer board 4 Layer board (-) only 2 layers available for routing traces and design a proper ground area (+) 4 layers available for routing traces and design a proper ground area (-) only 1 layer available for routing traces below the module (+) 3 layers available for routing traces below the module
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 22 of 36 (-) no separate VCC plane usable (+) separate VCC plane usable (+) cheaper than 4 layers (-) more expensive than 2 layers 9.5. Traces below the module Signal traces should not be placed directly below the module to avoid short circuits:  Traces on top layer are not allowed under the module (see Figure 11-2)  Traces on mid layers and bottom layers are allowed (see Figure 11-2) Figure 11-2: Layer design of 2 and 4 layer boards 9.6. Placement on the PCB The PCB design of the radio module base board and placement affects the radio pattern. For the deRFsamR21E-23S20 with coaxial u.FL connector usage, module placement is not critical, since the radiating part is placed external to the module and can therefore be placed everywhere on the board. If the RF-Pad is used, the placement shall be chosen for proper RF design. For deRFsamR21E-23S00 with integrated antenna the performance is strongly influenced by the base board design. The module shall be placed at the edge of the base board. The chip antenna has to be placed next to the edge as shown in the figures below. The antenna design is optimized for use on 1.5 mm FR4 PCB baseboard. Best performance is obtained with the module placed at the corner of the PCB with as much ground plane on the board as possible. Figure 11-3: Placing at the edge Figure 11-4: Placing at the centre edge Do not place the chip antenna radio module within the base board. This will cause a very poor radio performance. TopBottomMid 1Mid 22 Layer 4 LayerModule4 Layer Traces under module:Not allowedallowedallowedallowedTraces under module:Not allowedallowed
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 23 of 36 Figure 11-5: Placing in the centre with antenna Figure 11-6: Placing in the centre with RF pad Do not place ground areas below the radio module and near the chip antenna (see Section 11.5 and 11.7). 9.7. Recommended layout for deRFsamR21E-23S00 For best performance of the deRFsamR21E-23S00 with chip antenna it is recommended to place the module at a corner of the PCB according to Figure 11-7. Figure 11-7 recommended layout for deRFsamR21E-23S00 module The module antenna design of deRFsamR21E-23S00 is optimized for mounting on a standard technology PCB with the following properties:  Two-layer board  Board material FR4
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 24 of 36  Board thickness of 1.55 mm  Copper layer thickness of 35 µm  Top and bottom solder 9.8. RF Design for deRFsamR21E-23S20 For deRFsamR21E-23S20 two options for the RF signal are available: using the coaxial u.FL connector to connect an external antenna or if needed in the application, custom designed RF circuitry using the RF-out pad. Note: Please get in contact with dresden elektronik to advise for a custom FCC certified design. If necessary dresden elektronik can provide RF part design data. This may require signing a Non-Disclosure Agreement. When designing RF traces on the base board a line impedance of 50 Ω shall be used. Depending on the base board layer stack construction a microstrip or grounded coplanar microstrip design can be implemented. 9.8.1. External front end and antenna diversity The radio module deRFsamR21E-23S20 can be used with an external front end, including power amplifier (PA) for transmission and low noise amplifier (LNA) for receiving, and antenna diversity. Figure 11-8 shows a possible design as block diagram. A custom design can contain a single PA or single LNA or a complete integrated front-end chip. It depends mainly on the application. Furthermore, it is possible to include a RF switch for driving the antenna diversity feature. An example block diagram is shown in Figure 11-8. Figure 11-8: block diagram for external PA/LNA and antenna diversity control The DIG1 to DIG4 signals of the transceiver are connected internally to the microcontroller and have to be muxed on ports PA08, PA09, PA14 and PA15. DIG1 to DIG4 can be activated as alternate pin output functions FECTRL[0..5] by the microcontroller. Please refer to chapter 33 of ATSAMR21 datasheet [1]. Unbalanced RF output The radio module deRFsamR21E-23S20 has a 50 Ω unbalanced RF output. For designs with external RF power amplifier a RF switch is required to separate the TX and RX path.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 25 of 36 RF switches to PA, LNA and antenna The switch must have 50 Ω inputs and outputs for the RF signal. The switch control can be realized with the DIG3 and DIG4 signal of the radio transceiver. Power amplifier (PA) The PA has to be placed on the TX path after the RF switch. It is important to regard the PA’s manufacturer datasheet and application notes, especially for designing the power supply and ground areas. A poor design could cause a very poor RF performance. For energy efficiency it is useful to activate the PA only during TX signal transmission. In this case the DIG3 signal can be used as switch for (de-)activating the PA. Some PAs have the possibility to set them into sleep state. This application can be realized via a dedicated GPIO pin. Band-pass filter (BPF) The use of a band-pass filter is optional. It depends on the PA properties. Some PAs have an internal BPF and other do not have. The BPF is necessary to suppress spurious emissions of the harmonics and to be compliant with national EMI limits. It is possible to use an integrated BPF part or discrete parts. The advantage of the first variant is that the BPF characteristic is known and published in the manufacturer’s datasheet. Low noise amplifier (LNA) The LNA can be used to amplify the received signal. Please refer to the manufacturer’s datasheet for a proper design. The control can be done by DIG4 signal. RF switch for antenna diversity The switch must have 50 Ω inputs and outputs for the RF signal. It is possible to use a separate switch with 2 inputs and 2 outputs or use another (third) switch following the switch required for the PA/LNA. Antenna diversity switching can be controlled via DIG1. Certification The customer has to ensure, that custom front-end and antenna diversity designs based on the radio module deRFsamR21E-23S20 meet all national regulatory requirements of the assignment location and to have all necessary certifications, device registration or identification numbers.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 26 of 36 10. Programming The update process of the radio module, the required software and hardware for programming via SWD interface and the driver installation on different operating systems are described in this chapter. Currently, the SWD interface is supported by several Atmel and third party programmers and debuggers like Atmel ICE and Segger J-Link. Other programmers that support ATSAMR21E18A will work as well. For the programming the standard SWD header is recommended as 10pin 1.27 mm header as shown in Figure 12-1. Figure 12-1: Programming header 10.1. Software/Applications For software development several options are available depending on your needs:  For low-cost embedded wireless applications the MiWi Stack from Microchip supports the ATSAMR21. More information can be found at http://www.microchip.com/design-centers/wireless-connectivity/embedded-wireless/802-15-4/software/miwi-protocol  For ZigBee 3.0 home automation projects Microchip offers the ZigBee 3.0 BitCloud software stack. This stack is platform certified by the ZigBee Alliance. For more information see http://www.microchip.com/design-centers/wireless-connectivity/embedded-wireless/802-15-4/zigbee-3-0 Please contact your local Microchip Sales Representative to get access to the BitCloud Software Development Kit.  In Atmel Studio the Atmel Software Framework (ASF) offers a big number of examples for ATSAMR21G18A. It is the same controller in a package with more GPIO Pins available for the user. Some minor adjustments are necessary to allow the examples to run on ATSAMR21E18A on this module. Suitable compilers are GCC (v4.5.2) or IAR Compiler(IAR C/C++ Compiler for ARM v7.80.1) for example. Dresden elektronik offers software development services for with comprehensive experience in ZigBee 3.0 and IEEE 802.15.4 wireless applications. 10.2. Clocks The controller runs on 8 MHz RC-oscillator by default. Since the internal clock generation is not very accurate, it is recommended to use the external transceiver oscillator to avoid problems during communication for example by UART. To change the clock source to the precise transceiver oscillator (±10 ppm at 25°C) the transceiver has to be configured for clock output (CLKM) and the clock source at the controller has to be set to „GLCKIN“/“ GCLK_IO[1]“. During deep sleep operation the clock source is best set to „OSCULP32K“ for minimized current consumption. Further information can be found in [1].
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 27 of 36 10.3. Pre-flashed firmware The radio modules will be delivered without pre-flashed firmware. Dresden elektronik provides development services for industrial or ZigBee 3.0 compatible projects and the modules can be delivered with custom firmware pre-programmed.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 28 of 36 11. Radio certification The modules deRFsamR21E-23S00 and deRFsamR21E-23S20 have received regulatory approvals for modular devices in the United States and European countries. The modules were also successfully tested according to IC regulations and are compliant but not certified for Canada. 11.1. United States (FCC) The deRFsamR21E-23S00 with onboard chip antenna and deRFsamR21E-23S20 with coaxial u.FL connector comply with the requirements of FCC part 15. To fulfil FCC Certification requirements, an OEM manufacturer must comply with the following regulations: The modular transmitter must be labelled 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. Sample label for radio module deRFsamR21E-23S00 and deRFsamR21E -23S20: Contains FCC-ID: XVV-23SXX 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. The Original Equipment Manufacturer (OEM) must ensure that the OEM modular transmitter must be labelled with its own FCC ID number. This includes a clearly visible label on the outside of the final product enclosure that displays the contents shown below. If the FCC ID is not visible when the equipment is installed inside another device, then the outside of the device into which the equipment is installed must also display a label referring to the enclosed equipment. This equipment 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 (FCC 15.19). Installers must be provided with antenna installation instructions and transmitter operating conditions for satisfying RF exposure compliance. This device is approved as a mobile device with respect to RF exposure compliance, and may only be marketed to OEM installers. Modifications not expressly approved by this company could void the user's authority to operate this equipment (FCC section 15.21). This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 29 of 36 11.2. European Union (ETSI) Hereby, dresden elektronik ingenieurtechnik gmbh declares that the radio equipment types deRFsamR21E-23S00 and deRFsamR21E-23S20 are in compliance with the Directive 2014/53/EU. The full text of the EU declaration of conformity is available at the following internet address: https://www.dresden-elektronik.de/funktechnik/solutions/wireless-light-control/eu-conformity/?L=1. If the deRFsamR21E-23S00 and deRFsamR21E-23S20 modules are 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 VI of the Radio Equipment Directive 2014/53/EU. The manufacturer must maintain a copy of the deRFsamR21E-23S00 and deRFsamR21E-23S20 modules documentation and ensure the final product does not exceed the specified power ratings, antenna specifications, 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 must be respected.  The CE marking must have a height of at least 5 mm 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 can be found in [3].
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 30 of 36 11.3. Approved antennas The deRFsamR21E-23S00 has an integrated chip antenna. The design is fully compliant with all regulations. The deRFsamR21E-23S20 is compliant with the listed approved antennas in Table 13-1. Table 13-1: Approved antenna(s) and accessory Approved antenna list Type Gain Mount Order code Vendor / Supplier External antenna 2400 to 2483.5 MHz Rubber antenna +5dBi (peak) RP-SMA 17013.RSMA WiMo U.FL-to-RP-SMA pigtail, 15 cm -0.5dB BN-023769 dresden elektronik Integrated antenna 2400 to 2483.5 MHz Chip antenna +0.5dBi (peak) SMT AMCA31-2R450G-S1F-T Abracon LLC According to FCC KDB 178919 [5] it is allowed to substitute approved antennas through equivalent antennas of the same type with equal or less antenna gain: ‘Equivalent antennas must be of the same type (e.g., yagi, dish, etc.), must be of equal or less gain than an antenna previously authorized under the same FCC ID, and must have similar in band and out-of-band characteristics (consult specification sheet for cutoff frequencies).’
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 31 of 36 12. Ordering information The product name includes the following information: Table 14-1: Product name code Product name code Information Code Explanation Product / Chipset samR21E ATSAMR21E18A Frequency Range 2 2.4 GHz Flash memory 3 256 kByte Series S OEM module 2nd generation Features 00 Onboard chip antenna 20 Coaxial u.FL connector and RF-OUT pad Table 14-2: Ordering information Ordering information order number Product name Comments BN-600097 deRFsamR21E-23S00 solderable radio module with onboard chip antenna, no pre-flashed firmware BN-600098 deRFsamR21E-23S20 solderable radio module with coaxial u.FL- connector and RF-OUT pad, no pre-flashed firmware The modules will be delivered in Tape & Reel, for details see section 13. deRF xxxx - x x x xxFeaturesForm FactorFlash MemoryFrequency RangeProduct / Chipset
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 32 of 36 13. Packaging dimension The modules will be delivered in Tape & Reel. The reel quantity is 800 pcs, lower quantities will be delivered in cut tape. Tape dimensions Reel dimensions All dimensions are nominal and measured in mm.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 33 of 36 14. Soldering profile Table 16-1 shows the recommended soldering profile for the radio modules. Table 16-1: Soldering Profile Profile Feature Values Average-Ramp-up Rate (217°C to Peak) 3°C/s max Preheat Temperature 175°C ±25°C 180 s max Temperature Maintained Above 217°C 60 s to 150 s Time within 5°C of Actual Peak Temperature 20 s to 40 s Peak Temperature Range 260°C Ramp-down Rate 6°C/s max Time 25°C to Peak Temperature 8 min max Figure 16-1 shows a recorded soldering profile for a radio module. The blue colored line illustrates a temperature sensor placed next to the soldering contacts of the radio module. The pink line shows the set temperatures depending on the zone within the reflow soldering machine. Figure 16-1: Recorded soldering profile A solder process without supply of nitrogen causes a discoloration of the metal RF-shielding. It is possible that the placed label shrinks due the reflow process. 406080100120140160180200220240260280020406080100120140160180200220240260280300320340360T [°C] t [s] Measured Temp. Zone Temp.
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 34 of 36 15. Revision notes Actually, no design issues of the radio modules are known. All errata of the ATSAMR21E18A are described in the datasheet [1].
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 35 of 36 16. References [1] ATSAMR21E18A: Atmel SAM R21E / SAM R21G, SMART ARM-Based Wireless Microcontroller; Datasheet, URL: http://www.microchip.com/wwwproducts/en/ATSAMR21E18A [2] AT86RF233: Low Power, 2.4GHz Transceiver for ZigBee, RF4CE, IEEE 802.15.4, 6LoWPAN, and ISM Applications; Datasheet, URL: http://www.microchip.com/wwwproducts/en/at86rf233 [3] Directive 2014/53/EU, European Parliament and the Council, 16 April 2014, URL: http://eur-lex.europa.eu/legal-content/en/ALL/?uri=CELEX:32014L0053 [4] Transmitter Module Equipment Authorization Guide; 996369 D01 Module Certification Guide; FCC OET; URL: https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?id=44637&switch=P [5] Permissive Change Policy; 178919 D01 Permissive Change Policy; FCC OET; URL: https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?id=33013&switch=P [6] 2.4GHz Chip-Antenna AMCA31-2R450G-S1F-T by Abracon LLC; Datasheet; URL: http://www.abracon.com/chip-antenna/AMCA31-2R450G-S1F-T.pdf [7] 2.4GHz Rubber antenna 17013.xx by WiMo Antennen und Elektronik GmbH; Datasheet; URL: http://www.wimo.com/download/17013.pdf [8] Schematic and footprint library for Altium Designer®; URL: http://www.dresden-elektronik.de/funktechnik/service/downloads/documentation/?eID=dam_frontend_push&docID=2024 [9] Schematic and footprint library for EAGLE®; URL: http://www.dresden-elektronik.de/funktechnik/service/downloads/documentation/?eID=dam_frontend_push&docID=2023 [10] STEP model library for CAD tools; URL: http://www.dresden-elektronik.de/funktechnik/service/downloads/documentation/?eID=dam_frontend_push&docID=2022 [11] Link Config file Atmel Start [12] Flash AT25SF041 by Adesto; Datasheet; URL: https://www.adestotech.com/wp-content/uploads/DS-AT25SF041_044.pdf [13] Flash MX25V4006E by Macronix; Datasheet; URL: http://www.macronix.com/Lists/Datasheet/Attachments/6217/MX25V4006E,%202.5V,%204Mb,%20v1.9.pdf [14] Flash W25X40CL by Winbond; Datasheet; URL: http://www.winbond.com/resource-files/w25x40cl_f%2020140325.pdf [15] Flash W25X40CL by Winbond; Datasheet; URL: http://www.winbond.com/resource-files/da00-w25q40cle1.pdf
datasheet Version 0.9 2017-09-13 deRFsamR21E-23S00/-23S20 datasheet www.dresden-elektronik.de Page 36 of 36 dresden elektronik ingenieurtechnik gmbh Enno-Heidebroek-Straße 12 01237 Dresden GERMANY Phone +49 351 31850-0 Fax +49 351 31850-10 Email wireless@dresden-elektronik.de Trademarks and acknowledgements  IEEE 802.15.4™ is a trademark of the Institute of Electrical and Electronics Engineers (IEEE).  ZigBee® is a registered trademark of the ZigBee Alliance. All trademarks are registered by their respective owners in certain countries only. Other brands and their products are trademarks or registered trademarks of their respective holders and should be noted as such. Disclaimer This note is provided as-is and is subject to change without notice. Except to the extent prohibited by law, dresden elektronik ingenieurtechnik gmbh makes no express or implied warranty of any kind with regard to this guide, and specifically disclaims the implied warranties and conditions of merchantability and fitness for a particular purpose. dresden elektronik ingenieurtechnik gmbh shall not be liable for any errors or incidental or consequential damage in connection with the furnishing, performance or use of this guide. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or any means electronic or mechanical, including photocopying and recording, for any purpose other than the purchaser’s personal use, without the written permission of dresden elektronik ingenieurtechnik gmbh. Copyright © 2017 dresden elektronik ingenieurtechnik gmbh. All rights reserved.

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