Tag Archives: ATmega256RFR2

BitCloud ZigBee PRO SDK achieves Golden Unit status

Compatible with the Atmel | SMART SAM R21 and ATmega256RFR2, the BitCloud ZigBee PRO Software Development Kit has achieved Golden Unit status.

Atmel has announced that the BitCloud ZigBee PRO Software Development Kit (SDK) has achieved the prestigious Golden Unit status for the ZigBee PRO R21 standard. As an approved Golden Unit, the Atmel BitCloud solution will be used by ZigBee testhouses to verify standard compliancy for all future ZigBee 3.0 products. This guarantees superior interoperability for customers designing the latest connected lighting, security and comfort control products for smart home applications.


With improved security, interoperability and ease-of-use, the Atmel BitCloud SDK provides a comprehensive set of tools to quickly design and develop wireless products compliant to ZigBee LightLink and ZigBee Home Automation Profiles, as well as the upcoming ZigBee 3.0 standard. The BitCloud SDK includes full-featured reference applications, ZigBee PRO stack libraries and API, user documentation, and implements reliable, scalable and secure wireless solution that supports large mesh networks of hundreds of devices, and is optimized for ultra-low power consumption with up to 15 years battery life.

BitCloud ZigBee PRO SDK fully supports Atmel | SMART SAM R21 devices, a single-chip solution integrating Atmel’s Atmel | SMART ARM Cortex-M0+-based MCU and high-performance IEEE 802.15.4 RF transceiver available as a standalone component or production-ready certified modules. The Atmel BitCloud is also compatible with the AVR ATmega256RFR2 wireless MCU, an ideal hardware platform delivering the industry’s lowest power consumption at 12.5mA in active receive mode, combined with receiver sensitivity at 101dBm.


“Intelligence, wireless connectivity and security are key elements to enable the anticipated growth of the Internet of Things market,” says Pierre Roux, Atmel director of wireless solutions. “Achieving the prestigious Golden Unit Status for our BitCloud SDK ensures designers that our wireless solutions are world class and will cater next-generation solutions for this smart, connected world. We are excited to achieve this certification again.”

Squirco is a smart home system and sensor network

Maker develops a smart home system with self-learning capabilities, using sensors hidden in every room.

Undoubtedly, the rise of the Internet of Things has ushered in a big wave of smart devices. Packed with sensors, these gadgets will ultimately revolutionize the way in which people go about their daily lives — at work, in the car and at home. With respect to the latter, a recent Hackaday Prize entrant by the name of Steven points that there are two basic building blocks for constructing a connected home: a sensor network and an A.I.-based control system. In other words, a smart house can only be “smart” when a complete set of information is sent to the A.I., which in turn, figures out what to do autonomously. Otherwise, it just becomes another thing to point a remote control at.


“Instead of automating anything, all they give you is the power of remote control. These systems also have little to no intelligence, and mostly rely on the users to set up every minuscule detail about how the system should operate. As a result, a tremendous amount of work is added to the user (which completely defeats the purpose of a smart home system), and sealing off regular, non-tech users from joining the fray,” Steven writes.

While there are a number of sensors available on the market today, a vast majority are battery-powered and are far too conspicuous to be adorning the walls. With that in mind, the Maker has developed a new approach with his self-learning Squirco Smart Home System that uses a series of sensors hidden within light switches throughout each room.


Why light switches, you may ask? “They are plugged into the mains, which means they never run out of power. They are present in every room, which means the data set will be complete. They are inconspicuous, because they’re everywhere,” Steven explains.

The Maker has his sights on curating a complete set of data that would be provided to an A.I. unit and used to learn in-home behaviors. This basic set of information includes lighting conditions, temperature and humidity and human presence.


The system itself is based on an ATmega256RFR2 along with a Bluetooth Low Energy MCU. With this, Steven has managed to enable automatic smart bulb discovery and pairing, light use pattern learning, precise climate control with his Nest thermostat, presence learning that allows messages to be sent to a smartphone when someone is detected in or around the home, as well as a ‘vacation mode’ which triggers lights to make it appear as though someone is home while away. Beyond that, he has embedded an iBeacon in each switch, along with the learned usage patterns, to put the most relevant lighting control right at a user’s finger tip.

The electronics are all housed inside a 3D-printed case, while powered via microUSB. In order to simplify the user experience, Steven decided to forgo gesture control and instead leave it to pushing the button. He adds, “It was very important to get the feel of the click just right. The click had to have a sharp, tactile feel, and also have the right amount of travel.”


Over the course of his prototyping process, Steven has modified various components, which he elaborately lists in his Hackaday.io page’s log section. Among those tweaks included moving around its LEDs and PIR, repositioning pin headers, and even toying around with an ATtiny85 to control the relay. Want to learn more about the project? Head over to its official page here.

Apio is an IoT platform that lets you build smart devices

Apio lets you create smart objects in five minutes, while its SDK guides you along the way. 

Apio is an open-source platform for the Internet of Things, which lets Makers and designers create their own smart systems and connected objects in a matter of minutes. The platform is comprised of two USB devices, the General and Dongle, both of which are based on an ATmega256RFR2 and ATmega16U2, along with a custom operating system and SDK.

The General is a low-cost, low-power board that communicates wirelessly with the Dongle. This is tasked with connecting up to 65,000 General units, and through the Apio OS, controlling them via a mobile device or PC.


The General is entirely Arduino-compatible, which means users can write their own code in the Arduino IDE, and features an integrated IEEE 802.15.4 communication channel, the LWM. This allows for every board to “talk” with one another in a wireless mesh network. Apio makes it super easy for Makers to get started right out of the box, thanks to a comprehensive set of libraries. Being open-source, more advanced users can also modify existing or write their own codes, thanks to a powerful framework that supports a number of applications including IFTTT, Unity3D and Temboo.


So, what sort of IoT applications can the General be used for? For starters, Makers can develop an automatic watering system that lets them know when their plants are thirsty, or smarten existing household units like a smoke alarm or thermostat. Additionally, users can design an intelligent set of blinds or even connect a General to an electronic door lock to access remotely. The possibilities are endless.


Meanwhile, the Dongle connects wirelessly to each General through the Apio’s OS, permitting anyone to control the boards from a smartphone, tablet or PC. The Apio Dongle integrates with Atmel’s Lightweight Mesh protocol using the ATmega256RFR2, which paves the way for all single devices to become signal repeaters. The signal becomes stronger as the devices are brought closer, therefore overcoming Wi-Fi’s typical coverage problems. According to the team, Atmel’s LWM combined with XBee can provide a more affordable, lower power solution than Wi-Fi when it comes to radio communication. Beyond that, the pairing of a Dongle and a Beaglebone Black or Raspberry Pi gives users the ability create their own smart home gateway.

“With Apio, you can interact with your creations as in an orchestra and you’re the leader. You don’t need wires or expensive installations to create your own symphony,” the team explains.

Interested? You can delve deeper into the IoT platform on its official page here, or its detailed Wiki page here.

This DIY monitor measures water usage throughout your house

While we may not be able to fix the drought, one Maker has set out to change how we use water at home.

As many of you are aware, California is currently facing one of the most severe droughts on record. While it may be a bit difficult to enact immediate change at the municipal level, we can drastically alter how we use our water at home. With this in mind, Maker Will Buchanan recently decided that it would be a good idea to focus his energies toward reshaping our consumption habits.


“It’s possible to dramatically change our behavior simply by making us aware, but we simply don’t know where our water goes. A bill at the end of the month doesn’t give you much useful information, and it gives you the information a month too late,” Buchanan writes.

Inspired by an earlier low-cost water flow sensor project, the Maker devised a plumbing-free, home automation system that can track water usage in real-time across in-home fixtures. This was done by employing a piezo buzzer and a Pinoccio mesh networking device.


For those unfamiliar with the IoT startup, a Pinoccio Scout is a pocket-sized board packed with wireless networking, a rechargeable LiPo battery, some sensors, and the ability to expand its capabilities through shields, much like an Arduino. It is equipped with an ATmega256RFR2 and a single-chip AVR 8-bit processor, along with a low power 2.4GHz transceiver for IEEE 802.15.4 communications.

In order to get a comprehensive idea of where the water goes, Buchanan thought it would be a good idea to monitor it at the outlet as well as the inlet. Through visual queues (such as light color, duration and intensity) at each fixture, the system can inform a user as to how much water they are using at any given moment.


Beyond that, he wanted the mechanism to relay the information to the cloud, where the data could be parsed and visualized in a “household usage” dashboard using Plotly’s streaming API. To accomplish this, the Maker created a source stream via Pinoccio and a destination stream with data.sparkfun.com, while Python was used to bridge the selected data. Buchanan then uploaded an Arduino code onto his respective wireless Field Scouts.

While this DIY system may not solve the impending crisis, it is surely a start. Not to mention, the monitor may make for a great Hackaday Prize submission. So if you’re ready to save the world one drop at a time, head over to the project’s detailed page here.

Set it and forget it! Sprinkl is a smart irrigation system

Let’s face it, not only can watering your lawn can be a hassle, it can often times be a waste of resources as well. Luckily, Dallas-based startup Sprinkl has developed a smarter way to automate lawn sprinklers capable of reducing water usage by up to 50%. Not only is it great for your water bill, but is surely good news for drought-ridden homeowners throughout the country.


The innovative system is comprised of a patent-pending controller and multiple sensor units. Each weatherproof wireless sensor unit relays soil measurements back to the controller using a power-efficient 802.15.4 mesh network — driven by an ATmega256RFR2 — where additional information, such as local watering restrictions, is used to determine per-zone watering schedules.

Sprinkl is built on the Android OS, runs on a 1GHz processor and can even last seven years on a single lithium battery. Equipped with a capacitive touchscreen, the team stuck on some valve controls, enabling the system to command separate zones. Currently, Sprinkl comes in both 8- and 16-zone packages.


Furthermore, the smart irrigation system is also Wi-Fi enabled, meaning that it can pull weather forecasts and water conservation schedules directly from the cloud. Once watering and soil measurements are uploaded, homeowners can easily plot the data in their web browsers. Think of it of as a Nest thermostat for your lawn. Based on the sensors’ readings, the controller determines just the right amount of water to distribute.


According to our friends at PubNub, Sprinkl needed a real-time infrastructure to power their mobile API integration layers with their cloud system to ensure that its cloud and mobile apps were up-to-date based on any changes happening on a user’s controller. In order to achieve just that, Sprinkl seamlessly implemented the PubNub Data Stream Network, significantly reducing development time, as well as development complexity for their real-time backend.

“The Internet is at turning point in the home. Lighting and HVAC controllers have really evolved over the past four years, but irrigation and lawn care technology have been lagging behind,” explained Noel Geren, Managing Member of Sprinkl. “With Sprinkl we wanted to bring an evolutionary product to market; a gorgeous and extensible Android touch based controller that can automatically determine how much water to use per-zone, saving up to 50% on monthly watering bills and preserving earth’s precious resources.

Sprinkl is an ideal alternative for those looking for a smarter, more intuitive watering system for their lawns and landscapes. Interested in learning more? Head over to its official website here.


RF Modules: A low risk path to wireless success

It is rare for a day to go by without having at least one conversation with an embedded developer, project manager, Maker / hacker or hobbyist where the subject of the Internet of Things (IoT) and/or wireless connectivity does not come up in discussion.

Today, IoT is certainly a major focus in product development and wireless is a major component of that solution. Usually, my conversation centers around comments from product developers regarding how difficult it is to develop a production ready wireless product on the first pass; it is especially difficult for the growing number of product developers or Makers that are just getting their feet wet in wireless design and development.

Only the very experienced RF designers are willing to start from scratch when beginning a new wireless product design. For the rest of us, we look for proven reference designs and more recently, the first thing we browse for is an off-the-shelf certified module.

In comes Atmel! The company has recognized for a while that RF modules provide a low risk path to success, for those seeking to add wireless connectivity to their product. And, it is this realization that has led to a growing family of RF modules to meet one’s wireless needs in Wi-Fi, 802.15.4, and BLE coming soon.

Examples of 802.15.4 Zigbit wireless modules.

The certified wireless module approach turns a complicated RF design task into an easier, more manageable digital peripheral interface task. Don’t misunderstand me, one still must be careful and adhere to best practices in your embedded PCB design to support an RF module; however, it is a much easier to be successful on the first go-around when using an RF module than it would be starting from a chipset or IC layout and design.

typical wireless module

A typical wireless module with on board “chip” antenna (white rectangle shown in image).

For the most part, the layout of impedance controlled traces, and antenna layout and matching are all taken care of for you when using a module. Usually, the most difficult thing you have to consider is placement of the module on your target or carrier board, such that your placement does not adversely affect the radiation pattern or tuning of the antenna.

Not only does the design become simpler, but the costs associated with getting a wireless device to market becomes lower.  Because in general, all of the fees and time associated with governmental certification testing for agencies like the FCC, CE and IC (Industry Canada), are already taken care of for you. Also in most cases, the modules are shipped with a unique IEEE MAC address pre-programmed into the module’s non-volatile memory, so that each unit has a world wide unique address. By using a module that contains this pre-programmed assigned address, you can avoid the costs of obtaining a block of IEEE addresses assigned to your company.

At first glance, the cost of using a complete pre-certified RF module in a production design, as compared to implementing one’s own chip set design may appear more expensive. However, for those doing this for the first time with a staff that does not have a lot of RF design and certification experience, the hidden costs and time required to achieve the performance your application requires and to get the product into the market, leads to a lot of unwanted surprises requiring multiple attempts to achieve the final goal. Starting with a module helps get the product into the market faster with less risk, and provides a way to get product acceptance, before having to deal with cost reduction activity’s that may require moving from a module solution to a chip set solution.

For those that get to the position where the use of a pre-certified module on a proven product requires a cost reduction, Atmel has a solution ready for you. Each of the Atmel Zigbit modules have complete Altium design files and Gerber files available for free download via the Atmel website. This will enable you to take the exact design files that were used to create the module you were using or considering, and to use these files to devise your own version of that design. You can then have your new chip based layout manufactured by your own contract manufacturer; thus, you do not have to start over from the beginning and you already know that this RF design works well and can be easily certified. Governmental certification of your own board layout would be required, and in the case of the United States, you would be given your own FCC ID assigned to your company for this product.

For those product designers that are experienced in RF layout and design, a module can allow you to create a proof-of-concept product prototype very quickly and with little effort. Once the concepts have been proven and features have been decided upon, you can migrate from module to chip set design for high volume production.

Software developers, Makers, and hobbyists can eliminate a lot of the issues often found when trying to create low volume wireless products by obtaining one of the many Atmel evaluation boards that contain a wireless module.

These boards typically come with a bootloader and with some form of pre-loaded firmware to get you started immediately. You can explore that topic in more detail in an earlier Bits & Pieces post that describes the wireless composer and the Performance Analyzer firmware.

The Performance Analyzer firmware is what typically comes pre-installed on a Zigbit module “evaluation” board. Otherwise, the module itself would come with only a pre-programmed bootloader.

module evaluation board

You can learn more and download user guides / datasheets for the Atmel Zigbit modules via this link.

With the Internet of Things becoming such a focus at this time, you may want to get started with a pair of low-cost wireless module evaluation boards and use this platform to learn wireless connectivity techniques that can be used in your current or future job.  Demand for those with knowledge and experience in wireless connectivity and embedded systems is growing greater everyday.

Whether you’re a Maker or an engineer that wants to create a home project that requires a microcontroller and some type of wireless connectivity, you might want to take a look at the ATZB-256RFR2-XPRO evaluation board that includes the ATZB-S1-256-3-0-C module already mounted on it. This module is based upon the megaAVR microcontroller core and includes an 802.15.4 2.4ghz radio as a peripheral/.You may recognize the megaAVR core as being the same MCU core as used in the well-known and incredibly popular Arduino Uno board. You can use the familiar Arduino IDE for development and many of the Arduino libraries available on the internet will run directly on this module. Additionally, you can also find a bootloader and sample Lwmesh (Light Weight Mesh wireless networking) applications for this module here. (Search for for “ATmega256RFR2 Arduino Solution.”)

Look to our friends at Adafruit and Sparkfun to obtain various sensor breakout boards to complete your wireless connectivity projects.

Do you have big ideas? You can feel confident that with the 256k of flash program memory and the 32k of data sram available with the ATZB-S1-256-3-0-C module, as you will be able to create any Arduino application that comes to mind. And don’t forget, you have an onboard 802.15.4 2.4Ghz radio for your wireless connectivity needs. If you find you need additional features in your development and debug tools, you can simply move to Atmel Studio with its rich set of features.

Calling all Radio Amateurs CQ CQ CQ de NS1C… 

Are you now, or have you been in the past, involved in Amateur Radio? Have you been dreaming about QRP low power radios that are very small, battery operated, a complete radio solution, and cost in the $29 to $39 dollar range? You’re in luck — boards and modules are available that operate in the 915mhz or 2.4ghz radio bands! As a HAM radio operator, you are allowed to take the capabilities of these 802.15.4 radio modules even further than an engineer who is required to create a license free ISM radio solution. You can experiment with additional RF output power and experiment with high gain directional antennas (use the modules with u.FL RF connectors).

Maybe a nice field day project for next year would be to use a low power 15.4 radio from the top of a mountain or high hill and use mesh networking to see how many hops a group of participants can communicate over. Voice communication certainly could be implemented using external analog circuitry and some additional software; however, when getting started, you could stick to digital data communications or use the wireless microcontrollers to control or monitor other components of your Amateur radio station.

Parents teach your children…. or maybe, children teach your parents!

I am sure that everyone can think of many home or science fair projects where a parent and child can work together (hardware / software / documentation) and everyone can learn something new. Heck, in the end, you may actually invent the next great product that your family can introduce to the world!

Your possibilities are endless.

Atmel’s ATmega256RFR2 gets Xplained

An IEEE 802.15.4 compliant single chip combines an AVR microcontroller with a 2.4GHz RF transceiver. Simply put, Atmel’s ATmega256RFR2 offers the industry’s highest RF performance for single chip devices with a link budget of 103.5dBm, all while consuming 50% less current than existing products on the market today.

“The ATmega256RFR2 features hardware assisted multiple PAN address filtering (MAF), as well as improved channel masks on CH25 and CH26,” an Atmel engineering rep told Bits & Pieces.

“This allows the device to run full power (1W) on these channels using external power amplifiers, wake-on radio, improved link efficiency and reliability using RX override, 32-bit MAC symbol counter, temperature sensor, automatic transmission modes, 128-bit AES crypto engine, true random number generator, high data rate modes and antenna diversity support.”

To accelerate development with the ATmega256RFR2, Atmel offers the ATmega256RFR2 Xplained Pro, a hardware-based platform that allows engineers to more easily evaluate the device. Supported by Atmel Studio, the kit provides easy access to various ATmega256RFR2 features and explains how best to integrate the device in a customer design. Like other Atmel Xplained Pro evaluation kits, the ATmega256RFR2 Xplained Pro is capable of significantly expanding its original functionality by linking to additional Xplained Pro extension kits.

For a complete and ready to go package, the ATmega256RFR2-XSTK starter kit includes the Atmel I/O1 Xplained Pro, OLED1 Xplained Pro and PROTO1 Xplained Pro extension boards.

Aside from the ATmega256RFR2 microcontroller (MCU), key ATmega256RFR2 Xplained Pro specs include:

  • One mechanical reset button
  • One mechanical user pushbutton (wake-up, bootloader entry or general purpose)
  • One user yellow LED
  • 32.768kHz crystal
  • 16MHz crystal
  • 5 Xplained Pro extension headers (2 headers are duplicates)
  • Antenna diversity: Ceramic RF antenna and SMA connector for external antenna
  • Temperature sensor
  • Embedded debugger
  • Auto-ID for board identification in Atmel Studio 6.1
  • One yellow status LED
  • One green board power LED
  • Symbolic debug of complex data types including scope information
  • Programming
  • Data Gateway Interface: SPI, TWI, 4 GPIOs
  • Virtual COM port (CDC)
  • USB powered
  • Supported with application examples in Atmel Software Framework

The ATmega256RFR2 Xplained Pro can be purchased here from Atmel’s official store.

ATmega256RFR2 powers low-cost Ethernet to wireless gateways: Part 3

Earlier this week, Bits & Pieces introduced Atmel’s low-cost gateway (LCGW) reference design, powered by the versatile ATmega256RFR2 and WIZnet W5200. We explored the basics of the platform, including operation and CPU functions. We also took a closer look at the W5200 chip, memory, power system and antennae. Today, we will be diving into possible LCGW enclosures, regulatory compliance, debugging and software resources.

As we all know, users can be very creative with their enclosure designs. However, there are some basic guidelines for wireless devices. Perhaps most importantly, any metal or conductive material within 4 inches (10cm) of the antenna will have an effect on the far field radiation pattern. As such, metal enclosures should not be used. It is also recommended to keep metal parts such as screws, nuts and washers, metallic labels away from the PCB antenna area. Indeed, there are holes in the LCGW design which act as the preferred location for non-conductive fasteners.


In terms of regulatory compliance, the LCGW has been pre-tested for FCC Class B and CE compliance. Initial pre-scan data indicates this design is compliant with US and EU regulations. To obtain regulatory certification, developers will have to perform regulatory testing of their product in its final form – including enclosure and all application specific features. Although results may vary, the positive pre-scan results are reassuring and indicate the probability of successful certification is high.

The Atmel ATmega256RFR2 SoC used in the LCGW has a special Band-edge filter feature, which improves out-of-band rejection for channels 25 and 26 (2475 and 2480MHz.) The FCC defines a “Restricted Band” from 2483 to 2500MHz, meaning emissions in this Restricted Band are required to be below 54dBµV (500µV/m). Because of this requirement, many IEEE 802.15.4 devices are not able to use high power in channels 25 and 26. Nevertheless, the Band-edge filter feature of Atmel RFR2 radios allows the use of higher power in these channels. It should be noted that the FCC pre-scan data cited in this Bits & Pieces article was taken using the full output power of the  ATmega256RFR2  (+3.5dBm) and the Band-Edge feature enabled. The filer can be enabled by setting PLL_TX_FLT (bit 4) in the TRX_CTRL_1 (0x144) register.

On the debugging side, the DCP power inlet is fused for safety purposes. So if the Power-Good LED fails to light, be sure to check the fuse. If the fuse has blown and needs to be replaced, the root cause should be determined before putting the device back into service. For replacement parts, a 1 Amp 0603 SMT fuse is recommended (Bourns SF-0603S100, or equivalent). Do not use flipped CAT5 cables and be sure to exercise caution when connecting to Power Test Header J5, as this header exposes 5VDC and may damage low voltage GPIO or UART cables.

Although leveraging the 3.3V supply for light external loads is permissible, be advised that the 3.3V LDO has limitations on available line current, load current and thermal dissipation, so exceeding these limits may cause a malfunction. However, at maximum transmitter power, the Atmel  ATmega256RFR2  may exceed emissions limits in the 2483 to 2500MHz restricted band. This can be corrected by enabling the PLL_TX_FLT bit in the TRX_CTRL_1 register. Note – this special bandedge filtering feature of the Atmel RFR2 family allows use of high-power in channels 25 and 26.

Last, but certainly not least, Atmel supplies many network stacks that run on the ATmega256RFR2  These include the BitCloud ZigBee stacks, ZigBee Pro, ZigBee Light Link and ZigBee Home Automation, IEEE 802.15.4 MAC and the Atmel proprietary Light-Weight Mesh network stack.

Interested in learning more about Atmel’s low-cost gateway (LCGW) reference design? Be sure to check out part one  and two of this series.

ATmega256RFR2 powers low-cost Ethernet to wireless gateways: Part 2

Yesterday, Bits & Pieces introduced Atmel’s low-cost gateway (LCGW) reference design, powered by the versatile ATmega256RFR2 and WIZnet W5200. We explored the basics of the platform, including operation and CPU functions. And today we will be taking a closer look at the W5200 chip, memory, power system and antennae.


As noted in part one of this series, the W5200 chip can best be described as a hardwired TCP/IP embedded Ethernet controller that enables easier internet connection for embedded systems using Serial Peripheral Interface (SPI). W5200 is probably best suited for those users who require Internet connectivity for applications that use a single chip to implement TCP/IP stack, 10/100 Ethernet MAC and PHY.

Indeed, the W5200 is composed of a fully hardwired market-proven TCP/IP stack and an integrated Ethernet MAC and PHY. Hardwired TCP/IP stack supports TCP, UDP, IPv4, ICMP, ARP, IGMP and PPPoE – which has been proven in various applications for many years. W5200 employs a 32KB internal buffer as its data communication memory. By using W5200, users can implement the Ethernet application they need by using a simple socket program instead of handling a complex Ethernet Controller.

On the memory side, the LCGW is designed with two external memory devices onboard. More specifically, the Atmel AT24MAC402 2-Kbit TWI EEPROM is intended for persistent storage of EUI-48 or EUI-64 addresses. This device can be used to store MAC addresses, credentials, calibration data, manifests and security keys.

The AT24MAC EEPROM also has a hardwired address of 0x0, while the LCGW includes an Atmel AT45DB642 4-Mbit SPI flash memory for in-the-field upgrades, web-site storage, logs, electronic data sheets (TEDS) or general purpose scratch pad. Although these two memory devices are useful for gateway and data concentrator applications, they are optional and can be omitted to further reduce BOM cost.

In terms of power, DC power is derived from a USB Dedicated Charging Port (DCP) inlet.

“The LCGW can be powered from common mobile-device chargers or USB ports on Wi-Fi access points or PCs using a USB Micro-B cable. For safety, the power bus is protected by an SMT fuse and ESD/EMI suppression circuitry,” an Atmel engineering rep told Bits & Pieces. “USB supplies 5VDC, while a linear buck-regulator supplies the 3.3VDC rail for the CMOS devices. Connector J5 exposes the 5VDC and 3.3VDC rails for testing. The Power-Good indicator, D1, will light if both 5VDC and 3.3VDC are present. Additional low-voltage rails are regulated and filtered by the Ethernet sub-system.”

The engineering rep also noted that the the RF front end of the LCGW antenna is designed for low-cost and high efficiency.

“That is why a PCB dipole antenna was chosen – because it does not require an external balun or specialized RF components which add cost. Plus, the relatively large area of this dipole design significantly increases the effective area and antenna aperture,” the engineering rep continued. “Larger antenna aperture dramatically improves receiver efficiency, sensitivity and range. This dipole antenna offers performance superior to chip antennas for receiving weak signals from remote nodes in marginal conditions. This antenna design is on par with high-performance external monopole antennas at a fraction of the cost.”

In addition, the antenna radiation pattern of the LCGW is moderately directional. This can be used to advantage by adjusting the orientation to bring in weak signals. Conversely, conductive objects and obstructions can be placed in the null zones to reduce adverse effects. It should be emphasized, though, that the un-populated PCB area around the antenna is essential to sustain a strong electric field, which radiates from both sides of the PCB, top and bottom. As such, it is important to avoid placing conductors, labels or stickers in this area.

Interested in learning more about Atmel’s low-cost gateway reference design? Be sure to check back tomorrow for part three of our in-depth look at the ATmega256RFR2-powered LCGW.

ATmega256RFR2 powers low-cost Ethernet to wireless gateways: Part 1

Atmel’s low-cost gateway (LCGW) reference design – powered by the ATmega256RFR2 – is a turn-key production-ready solution that connects IEEE 802.15.4 wireless networks to wired Ethernet networks. This gateway allows IEEE 802.15.4 wireless devices to link with mobile devices such as smartphones and tablets running remote-control applications.


“The ATmega256RFR2 wireless system-on-a-chip (SoC) combines best-in-class radio performance with the efficient Atmel AVR 8-bit CPU,” an Atmel engineering rep told Bits & Pieces. “In short, the ATmega256RFR2 provides a responsive CPU and high-performance radio to address the demanding tasks of network coordinator and data concentrator.”

Meanwhile, the WIZnet W5200 embedded Ethernet controller features a 10BaseT/100BaseTX MAC and PHY, supporting numerous popular Ethernet protocols including TCP/IP, UDP and IPv4.

“Essentially, the wired Ethernet interface is a low-cost, reliable and secure connection that works with the end user’s existing routers, access-points, WLANs and ISPs,” the engineering rep continued. “Remember, wired Ethernet lowers cost and also avoids interference problems and regulatory issues inherent with co-located radio solutions.”


The engineering rep also noted that the reference design was formulated with low BOM cost as a primary objective. As such, the design is free of superfluous accessories and non-essential sub-systems, with a standard JTAG interface provided for programming and debug.

Atmel’s design includes optional EEPROM and Data-Flash memory sockets, while DC power is derived from a USB Micro-B Dedicated Charge Port (DCP) – allowing users to power the gateway with common phone chargers or from Wi-Fi Access Points via USB ports. As expected, both the USB and Ethernet connections have ESD/EMI suppression to improve reliability.

In terms of operation, connections to the LCGW are relatively simple. Connect the DCP to a USB power source using the Micro-B connector and D3 will light indicating DC power is ready. Then, connect the RJ45 Ethernet port to a router with a CAT5 patch cable.

“Atmel’s ATmega256RFR2 can be programmed and debugged using the 10-pin JTAG header and Atmel JTAGICE programmers. SW2 is a hardware RESET for the CPU, while Ethernet MAC Reset is driven by software,” the engineering rep explained. “And J5 exposes the power rails for testing. There are several user defined features: UART0, Port F GPIO, SW1 and D1 are uncommitted and available to the application developer.”


On the CPU side, Atmel’s  ATmega256RFR2 is a low-power CMOS 8-bit microcontroller based on AVR enhanced RISC architecture combined with a high data rate transceiver for the 2.4GHz ISM band. By executing powerful instructions in a single clock cycle, the device achieves throughputs approaching 1 MIPS per MHz allowing system designers to optimize power consumption versus processing speed. Meanwhile, the radio transceiver provides high data rates from 250kb/s up to 2Mb/s, frame handling, outstanding receiver sensitivity and high transmit output power enabling a very robust wireless communication.

Interested in learning more about Atmel’s low-cost gateway reference design? Be sure to check back tomorrow for part two of our in-depth look at the ATmega256RFR2-powered LCGW.