High-Current PC/104 Board Delivers 48 Channels of I/O

Apex Embedded Systems offers the TRACER-DIO-5VIO, a high current PC/104 digital I/O and counter/timer module. The module provides 48-lines of 8255 compatible general purpose I/O and three 16-bit 8254 compatible counter/timers. The board is a COTS module used in military, aerospace and industrial applications.
This product is an update from the company’s classic Tracer-E. The digital I/O module provides true 5 V output swings and accepts full 5 V inputs. It has 48-lines of 8255 compatible general purpose I/O and three 16-bit 8254 compatible counter/timers. Optional 2 mm connectors and cables, terminal board and cable accessories are available. A tin mitigation option available via special order. Firmware modifications are available on request.

Features:

  • High-Current Outputs can sink 32 milliamps, and source 32 milliamps per channel. This is true even while operating at high temperatures.
  • Direct Interfacing to OPTO-22’s isolated I/O racks. Digital I/O connector is organized to allow direct connection to OPTO-22’s isolated I/O racks that use the G4 serial of I/O modules, the PB16-H, PB16-J, PB16-K, PB16-L, PB8H and the PB24HQ.
  • Environmental: Wide operating temperature range of -40  to +85 degrees C
  • Polarized connectors prevent incorrect cable installations
  • LED status: an LED displays valid card read/write transactions useful for both product development and field status.
  • Single +5V operation: approximately 500 milliwatts (inputs/outputs unloaded)
  • Out-gassing and fire avoidance: They do not use any tantalum or electrolytic capacitors in any products.
  • Reliability: MTBF of 724,559 hours per MIL-HDBK-217F ground benign at 25o= degrees C.
  • Production: Designed and Assembled in Wisconsin, USA, utilizing an ISO 9001 manufacturing facility.

Apex Embedded Systems | www.apexembeddedsystems.com

 

Easing into the IoT Cloud (Part 2)

Modules in Action

In Part 1 of this article series, Brian examined some of the technologies and services available today, enabling you to ease into the IoT cloud. Now, in Part 2, he discusses the hardware features of the Particle IoT modules, as well as the circuitry and program code for the project. He also explores the integration of a Raspberry Pi solution with the Particle cloud infrastructure.

By Brian Millier

After looking at broader aspects of easing into the IoT Cloud in Part 1, now it’s time to get into the hardware and software details. Let’s take a look at three of the Particle modules, shown in Figure 1. The P0 module contains the Cypress Semiconductor BCM43362 Wi-Fi chip and STMicroelectronics STM32F205RGY6 120 MHz Arm Cortex M3 microcontroller (MCU), in a small surface mount package. The Photon module contains this P0 module, plus a 3.3 V switch-mode power supply regulator, USB socket, mode switches and an RGB LED—all mounted on a 24-pin DIP package. The Electron module contains the U-blox SARA-U260/U270 3G cellular modem, the STM32F205RGT6 120  MHz Arm Cortex M3 MCU, a BQ24195 power management unit/battery charger, a Maxim Integrated battery gauge IC, plus the same mode switches and RGB LED contained on the Photon. It is mounted on a larger, 36-pin DIP module.

Figure 1
Shown here are three of the Particle IoT modules. The two on the left are Wi-Fi, and the one on the right is 3G Cellular.

The Photon and Electron share a common set of peripheral ports. These include 1x 12- bit ADC with up to 8 inputs, 2x 12-bit DACs, 2x  SPI, 1x I2C, 1x I2S, 1x CAN, 1x USB, 9x PWM, 1x UART and 18x GPIO.

The Electron module, having 12 more pins, has more of some of the above peripheral ports. Because the peripheral ports of both modules occupy many of the available pins, there will be fewer GPIO pins available if you use some the peripheral ports.
Particle provides libraries or high-level APIs for just about all the peripheral ports I’ve listed. The only peripheral port that I found was not supported was the I2S block. I2S is basically a high-speed bus dedicated to audio DACs/ADCs/Codecs. Due to the high speed, synchronous data transfers that I2S devices demand, such devices are generally not compatible with the real-time operating system (FreeRTOS) that the

Particle device runs under (unless you use DMA-based I2S).
Particle’s GPIO, I2C and SPI API’s are written to be compatible with their counterparts in Arduino. Because of that, third-party Arduino libraries that are available for many common peripheral chips/breakout modules will work with the Particle modules without further tweaking.

Both the Proton and Electron come with a tiny U.FL socket for an external antenna. In the Electron, a Taoglas external antenna is required and is provided. The Photon has a small PCB-mounted Wi-Fi chip antenna, but you can also use an external antenna if you are mounting the Photon in a case that doesn’t allow RF to penetrate. There is an Automatic RF mode, where the best signal from either the chip or external antenna is used.

The Electron module can draw around 2 A or more when communicating with a cell tower. This is more current than can be supplied if you were to plug the Electron into a PC’s USB port. Although you can get USB adapters that supply greater than 2 A, you wouldn’t be able to communicate with the Electron via USB, which would be handy during debugging. Particle wisely decided to include a Li-Po battery charger on-board and included a 2,000 mA-hours Li-Po battery with JST plug in the Electron kit. This assures the user that there will be enough power available to operate the cellular modem’s RF circuitry at full power.

As of this writing, the Particle 3G Electron (in the DIP package) is only available in an educational “kit” format, which includes the Electron module, antenna, LiPo battery, USB cable and a small protoboard. With all those support components included, it’s a good deal at $69. The E-Series SMT module, meant to be integrated into a commercial product, is more expensive ($79 in unit quantities), and doesn’t include any of the support components in the Electron kit.

PROJECT CIRCUIT DETAILS

The first Particle-based project I built was the over-temperature alarm that I described in Part 1 of this series. It also sends out an alert if the power fails. Figure 2 is a schematic of the circuit. I decided to use the Dallas Semiconductor (now Maxim Integrated) DS18S20 1-wire temperature measurement device. It is more expensive than a thermistor, but is accurate to within ± 0.5°C and doesn’t need any calibration procedure. The Particle library contains a “ds18x20” library that handles both the DS18B20 and the DS18S20 devices. These two devices differ in that each one outputs temperature at a different resolution, and the library handles this transparently. The DS18x20 can be operated in a 2-wire mode—signal and parasitic power on one wire, and ground on the other. However, timing constraints are less onerous if you use separate wires for the signal and power lines, and that is how I wired mine.

Figure 2
Schematic diagram of the project, using an Electron Cellular module.

I chose a small Nokia 5110 LCD display for the user interface. These are inexpensive, as they are pulled from or are surplus units from popular older Nokia cell phones. An Arduino-based Nokia 5110 library works with Particle devices. This can be found in the “Library” section of the Particle Web-based IDE. The 5110 LCD has a separate backlight pin, which can be driven by a PWM signal, to control the backlight LED’s brightness. I run the backlight with a PWM duty cycle of 25%, which is plenty bright and uses less power.

The user controls are as follows:

1) An SPDT switch acts as the Setpoint UP/DOWN adjustment.
2) A TEST pushbutton, when pressed, simulates an over-temperature condition and sends out the same message for test purposes.
3) A RESET pushbutton is connected to the Electron module’s *RST pin.
4) While not shown in my diagram, I later added a switch in series with the Li-Po battery’s positive wire, to disconnect the Li-Po completely. This allows the unit to be turned off when the USB power adapter is unplugged and this switch is shut off.
The LCD displays the current time, which is synchronized with the Particle cloud server, so it’s very accurate. It also displays the measured temperature and the Setpoint temperature. The fourth line of the display indicates the AC power status. Because the power status is only monitored once per minute, it will not report a momentary power-loss.

Read the full article in the January 342 issue of Circuit Cellar

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Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

Pico-ITX and 3.5-inch SBCs Feature Dual-Core i.MX6 SoCs

IBASE Technology has announced two SBCs, both powered by an NXP i.MX 6Dual Cortex-A9 1.0GHz high performance processor. The IBR115 2.5-inch SBC and the IBR117 3.5-inch SBC are designed for use in applications in the automation, smart building, transportation and medical markets.
IBR115 and IBR117 are highly scalable SBCs with extended operating temperature support of -40°C to 85°C and an optional heatsink. Supporting 1 GB DDR3 memory on board, the boards provide a number of interfaces for HDMI and single LVDS display interface, 4 GB eMMC, Micro SD, COM, GPIO, USB, USB-OTG, Gbit Ethernet and a M.2 Key-E interface. These embedded I/Os provide connection to peripherals such as WiFi, Bluetooth, GPS, storage, displays, and camera sensors for use in a variety of application environment while consuming low levels of power.

Both models ship with BSPs for Yocto Project 2.0 Linux and Android 6.0. They both run on dual-core, 1 GHz i.MX6 SoCs, but the IBR115 uses the DualLite while the IBR117 has a Dual with a slightly more advanced Vivante GPU.

IBR115/IBR117 Features:

  • With NXP Cortex-A9, i.MX 6Dual-Lite (IBR115) / i.MX 6Dual (IBR117) 1GHz processor
  • Supports HDMI and Dual-channel LVDS interface
  • Supports 1 GB DDR3, 4 GB eMMC and Micro SD (IBR115) / SD (IBR117) socket for expansion
  • Embedded I/O as COM, GPIO, USB, USB-OTG, audio and Ethernet
  • 2 Key-E (2230) and Mini PCI-E w/ SIM socket (IBR117) for wireless connectivity
  • OpenGL ES 2.0 for 3D BitBlt for 2D and OpenVG 1.1
  • Wide-range operating temperature from -40°C to 85°C

IBASE Technology | www.ibase.com.tw

Wide Range Power Monitor Embeds ADCs

Analog Devices, acquired earlier this year by Linear Technology, has announced the LTC2992, a wide range I²C system monitor that monitors the current, voltage and power of two 0 V to 100 V rails without additional circuitry. The LTC2992 has flexible power supply options, deriving power from a 3 V to 100 V  monitored supply, a 2.7 V to 100 V secondary supply, or from the on-board shunt regulator. These supply options eliminate the need for a separate buck regulator, shunt regulator or inefficient resistive divider while monitoring any 0 V to 100 V rail. The LTC2992 is a simple, single-IC solution that uses three delta-sigma ADCs and a multiplier to provide 8- or 12-bit current and voltage measurements and 24-bit power readings.

LTC2992The LTC2992’s wide operating range is ideal for many applications, especially 48V telecom equipment, advanced mezzanine cards (AMC) and blade servers. The onboard shunt regulator provides support for supplies greater than 100V and negative supply monitoring. The LTC2992 measures current and voltage either continuously or on-demand, calculates power and stores all of this information along with minimum and maximum values in I²C accessible registers. Four GPIOs can also be configured as ADC inputs to measure neighboring auxiliary voltages. Measurements are made with only ±0.3% of total unadjusted error (TUE) over the entire temperature range. If any parameter trips the user-programmable thresholds, the LTC2992 flags an alert register and pin per the SMBus alert response protocol. The 400 kHz I²C interface features nine device addresses, a stuck bus reset timer, and a split SDA pin that simplifies I²C opto-isolation.  The LTC2992-1 version offers an inverted data output I²C pin for use with inverting opto-isolator configurations.

The LTC2992 and LTC2992-1 are offered in commercial, industrial and automotive versions, supporting operating temperature ranges from 0°C to 70°C, –40°C to 85°C and –40°C to 125°C, respectively. Both versions are available today in RoHS-compliant, 16-lead 4mm x 3mm DFN and 16-lead MSOP packages. Pricing starts at $3.85 each in 1,000-piece quantities. Please visit www.linear.com/products/power_monitors for more product selection and information.

Summary of Features:

  • Rail-to-Rail Input Range: 0 V to 100 V
  • Wide Input Supply Range: 2.7 V to 100 V
  • Shunt Regulator for Supplies >100 V
  • Three Delta-Sigma ADCs with Less Than ±0.3% TUE
  • 12-Bit Resolution for Currents & Voltages
  • Four GPIOs Configurable as ADC Inputs
  • Shutdown Mode with IQ < 50 µA
  • I²C Interface
  • Split SDA Pin Eases Opto-Isolation
  • Available in 16-Lead 4mm x 3mm DFN & 16-Lead MSOP Packages

Analog Devices | www.analog.com

Linear Technology | www.linear.com

Low Power PC/104-Plus SBC has Rich I/O

Winsystems has announced Its new PPM-C412 series for demanding environments and applications. It offers a broad spectrum of I/O features and the ability to expand functionality in a densely populated, standalone SBC solution. The board delivers greater performance and a clear upgrade path for current PPM-LX800 users while providing full ISA-compatible PC/104-Plus expansion.

WinSystems_PPM_C412At the heart of the board is a Vortex DX3 System on Chip (SOC), which offers a 32-bit x86 architecture with a dual-core microprocessor. The PPM-C412 incorporates dual Ethernet ports coupled with four serial ports, four USB channels and an LPT port for myriad communications options. It also includes dual simultaneous display outputs, one LVDS and one VGA, for Human Machine Interface (HMI) displays. Further, It provides 24 GPIO for monitoring and control, resulting in an I/O-rich, rugged SBC occupying minimal space. The PPM-C412 can be used on its own or in combination with the PC/104-Plus bus to expand functionality and capitalize on its full ISA compatibility, averting the need to re-engineer system architectures.

The PPM-C412 is specifically built for rugged industrial environments, with low power requirements, up to 2 GB RAM and an operating temperature range of -40ºC to +85ºC. With a 10-year availability, this new SBC also extends the product life of systems using commercial off the shelf (COTS) and proprietary PC/104 expansion modules.

Winsystems I www.winsystems.com

Sensor Node Gets LoRaWAN Certification

Advantech offers its standardized M2.COM IoT LoRaWAN certified sensor node WISE-1510 with integrated ARM Cortex-M4 processor and LoRa transceiver. The module the  is able to provide multi-interfaces for sensors and I/O control such as UART, I2C, SPI, GPIO, PWM and ADC. The WISE-1510 sensor node is well suited for for smart cities, WISE-1510_3D _S20170602171747agriculture, metering, street lighting and environment monitoring. With power consumption optimization and wide area reception, LoRa  sensors or applications with low data rate requirements can achieve years of battery life and kilometers of long distance connection.

WISE-1510 has has received LoRaWAN certification from the LoRa Alliance. Depending on deployment requirements, developers can select to use Public LoRaWAN network services or build a private LoRa system with WISE-3610 LoRa IoT gateway. Advantech’s WISE-3610  is a Qualcomm ARM Cortex A7 based hardware platform with private LoRa ecosystem solution that can connect up to 500 WISE-1510 sensor node devices. Powered by Advantech’s WISE-PaaS IoT Software Platform, WISE-3610 features automatic cloud connection through its WISE-PaaS/WISE Agent service, manages wireless nodes and data via WSN management APIs, and helps customers streamline their IoT data acquisition development through sensor service APIs, and WSN drivers.

Developers can leverage microprocessors on WISE-1510 to build their own applications. WISE-1510 offers unified software—ARM Mbed OS and SDK for easy development with APIs and related documents. Developers can also find extensive resources from Github such as code review, library integration and free core tools. WISE-1510 also offers worldwide certification which allow developers to leverage their IoT devices anywhere. Using Advantech’s WISE-3610 LoRa IoT Gateway, WISE-1510 can be connected to WISE-  PaaS/RMM or  ARM Mbed Cloud service with IoT communication protocols including LWM2M, CoAP, and MQTT. End-to-end integration assists system integrators to overcome complex challenges and helps them build IoT applications quickly and easily.

WISE-1510 features and specifications:

  • ARM Cortex-M4 core processor
  • Compatible support for public LoRaWAN or private LoRa networks
  • Great for low power/wide range applications
  • Multiple I/O interfaces for sensor and control
  • Supports wide temperatures  -40 °C to 85 °C

Advantech | www.advantech.com

Low-Power Micromodule

The ECM-DX2 is a highly integrated, low-power consumption micromodule. Its fanless operation and extended temperature are supported by the DMP Vortex86DX2 system-on-a-chip (SoC) CPU. The micromodule is targeted for industrial automation, transportation/vehicle construction, and aviation applications.
The ECM-DX2 withstands industrial operation environments for –40-to-75°C temperatures and supports 12-to-26-V voltage input. Multiple OSes, including Windows 2000/XP and Linux, can be used in a variety of embedded designs.

AvalueThe micromodule includes on-board DDR2 memory that supports up to 32-bit, 1-GB, and single-channel 24-bit low-voltage differential signaling (LVDS) as well as video graphics array (VGA) + LVDS or VGA + TTL multi-display configurations. The I/O deployment includes one SATA II interface, four COM ports, two USB 2.0 ports, 8-bit general-purpose input/output (GPIOs), two Ethernet ports, and one PS/2 connector for a keyboard and a mouse. The ECM-DX2 also provides a PC/104 expansion slot and one MiniPCIe card slot.

Contact Avalue Technology for pricing.

Avalue Technology, Inc.
www.avalue.com.tw

ARM mbed Platform for Bluetooth Smart Applications

OLYMPUS DIGITAL CAMERAThe nRF51822-mKIT simplifies and accelerates the prototyping process for Bluetooth Smart sensors connecting to the Internet of Things (IoT). The platform is designed for fast, easy, and flexible development of Bluetooth Smart applications.

The nRF51822 system-on-chip (SoC) combines a Bluetooth v4.1-compliant 2.4-GHz multiprotocol radio with an ARM Cortex-M0 CPU core on a single chip optimized for ultra-low-power operation. The SoC simplifies and accelerates the prototyping process for Bluetooth Smart sensors connecting to the IoT.

The nRF51822-mKIT’s features include a Bluetooth Smart API, 31 pin-assignable general-purpose input/output (GPIO), a CMSIS-DAP debugger, Programmable Peripheral Interconnect (PPI), and the ability to run from a single 2032 coin-cell battery.

Through mbed, the kit is supported by a cloud-based approach to writing code, adding libraries, and compiling firmware. A lightweight online IDE operates on all popular browsers running on Windows, Mac OSX, iOS, Android, and Linux OSes. Developers can use the kit to access a cloud-based ARM RVDS 4.1 compiler that optimizes code size and performance.

The nRF51822-mKIT costs $59.95.

Nordic Semiconductor ASA
www.nordicsemi.com

Remote Control and Monitoring of Household Devices

Raul Alvarez, a freelance electronic engineer from Bolivia, has long been interested in wireless device-to-device communication.

“So when the idea of the Internet of Things (IoT) came around, it was like rediscovering the Internet,” he says.

I’m guessing that his dual fascinations with wireless and the IoT inspired his Home Energy Gateway project, which won second place in the 2012 DesignSpark chipKIT challenge administered by Circuit Cellar.

“The system enables users to remotely monitor their home’s power consumption and control household devices (e.g., fans, lights, coffee machines, etc.),” Alvarez says. “The main system consists of an embedded gateway/web server that, aside from its ability to communicate over the Internet, is also capable of local communications over a home area wireless network.”

Alvarez catered to his interests by creating his own wireless communication protocol for the system.

“As a learning exercise, I specifically developed the communication protocol I used in the home area wireless network from scratch,” he says. “I used low-cost RF transceivers to implement the protocol. It is simple and provides just the core functionality necessary for the application.”

Figure1: The Home Energy Gateway includes a Hope Microelectronics RFM12B transceiver, a Digilent chipKIT Max32 board, and a Microchip Technology ENC28J60 Ethernet controller chip.

Figure 1: The Home Energy Gateway includes a Hope Microelectronics RFM12B transceiver, a Digilent chipKIT Max32 board, and a Microchip Technology ENC28J60 Ethernet controller chip.

Alvarez writes about his project in the February issue of Circuit Cellar. His article concentrates on the project’s TCI/IP communications aspects and explains how they interface.

Here is his article’s overview of how the system functions and its primary hardware components:

Figure 1 shows the system’s block diagram and functional configuration. The smart meter collects the entire house’s power consumption information and sends that data every time it is requested by the gateway. In turn, the smart plugs receive commands from the gateway to turn on/off the household devices attached to them. This happens every time the user turns on/off the controls in the web control panel.

Photo 1: These are the three smart node hardware prototypes: upper left,  smart plug;  upper right, a second smart plug in a breadboard; and at bottom,  the smart meter.

Photo 1: These are the three smart node hardware prototypes: upper left, smart plug; upper right, a second smart plug in a breadboard; and at bottom, the smart meter.

I used the simple wireless protocol (SWP) I developed for this project for all of the home area wireless network’s wireless communications. I used low-cost Hope Microelectronics 433-/868-/915-MHz RFM12B transceivers to implement the smart nodes. (see Photo 1)
The wireless network is configured to work in a star topology. The gateway assumes the role of a central coordinator or master node and the smart devices act as end devices or slave nodes that react to requests sent by the master node.

The gateway/server is implemented in hardware around a Digilent chipKIT Max32 board (see Photo 2). It uses an RFM12B transceiver to connect to the home area wireless network and a Microchip Technology ENC28J60 chip module to connect to the LAN using Ethernet.

As the name implies, the gateway makes it possible to access the home area wireless network over the LAN or even remotely over the Internet. So, the smart devices are easily accessible from a PC, tablet, or smartphone using just a web browser. To achieve this, the gateway implements the SWP for wireless communications and simultaneously uses Microchip Technology’s TCP/IP Stack to work as a web server.

Photo 2: The Home Energy Gateway’s hardware includes a Digilent chipKIT Max32 board and a custom shield board.

Photo 2: The Home Energy Gateway’s hardware includes a Digilent chipKIT Max32 board and a custom shield board.

Thus, the Home Energy Gateway generates and serves the control panel web page over HTTP (this page contains the individual controls to turn on/off each smart plug and at the same time shows the power consumption in the house in real-time). It also uses the wireless network to pass control data from the user to the smart plugs and to read power consumption data from the smart meter.

The hardware module includes three main submodules: The chipKIT Max 32 board, the RFM12B wireless transceiver, and the ENC28J60 Ethernet module. The smart meter hardware module has an RFM12B transceiver for wireless communications and uses an 8-bit Microchip Technology PIC16F628A microcontroller as a main processor. The smart plug hardware module shows the smart plugs’ main hardware components and has the same microcontroller and radio transceiver as the smart meter. But the smart plugs also have a Sharp Microelectronics S212S01F solid-state relay to turn on/off the household devices.

On the software side, the gateway firmware is written in C for the Microchip Technology C32 Compiler. The smart meter’s PIC16F628A code is written in C for the Hi-TECH C compiler. The smart plug software is very similar.

Alvarez says DIY home-automation enthusiasts will find his prototype inexpensive and capable. He would like to add several features to the system, including the ability to e-mail notifications and reports to users.

For more details, check out the February issue now available for download by members or single-issue purchase.

Turn Your Android Device into an Application Tool

A few years ago, the Android Open Accessory initiative was announced with the aim of making it easier for hardware manufacturers to create accessories that work with every Android device. Future Technology Devices International (FTDI) joined the initiative and last year introduced the FTD311D multi-interface Android host IC. The goal was to enable engineers and designers to make effective use of tablets and smartphones with the Android OS, according to Circuit Cellar columnist Jeff Bachiochi.

The FTD311D “provides an instant bridge from an Android USB port(B) to peripheral hardware over general purpose input-out (GPIO), UART, PWM, I2C Master, SPI Slave, or SPI Master interfaces,” Bachiochi says.

In the magazine’s December issue Bachiochi takes a comprehensive look at the USB Android host IC and how it works. By the end of his article, readers will have learned quite a bit about how to use FTDI’s apps and the FT311D chip to turn an Android device into their own I/0 tool.

Bachiochi used the SPI Master demo to read key presses and set LED states on this SPI slave 16-key touch panel.

Bachiochi used the SPI Master demo to read key presses and set LED states on this SPI slave 16-key touch panel.

Here is how Bachiochi describes the FT311D and its advantages:

The FT311D is a full-speed USB host targeted at providing access to peripheral hardware from a USB port on an Android device. While an Android device can be a USB host, many are mobile devices with limited power. For now, these On-The-Go (OTG) ports will be USB devices only (i.e., they can only connect to a USB host as a USB device).

Since the USB host is responsible for supplying power to a USB peripheral device, it would be bad design practice to enable a USB peripheral to drain an Android mobile device’s energy. Consequently, the FT311D takes on the task of USB host, eliminating any draw on the Android device’s battery.

All Android devices from V3.1 (Honeycomb) support the Android Open Accessory Mode (AOAM). The AOAM is the complete reverse of the conventional USB interconnect. This game-changing approach to attaching peripherals enables three key advantages. First, there is no need to develop special drivers for the hardware; second, it is unnecessary to root devices to alter permissions for loading drivers; and third, the peripheral provides the power to use the port, which ensures the mobile device battery is not quickly drained by the external hardware being attached.

Since the FT311D handles the entire USB host protocol, USB-specific firmware programming isn’t required. As the host, the FT311D must inquire whether the connected device supports the AOAM. If so, it will operate as an Open Accessory Mode device with one USB BULK IN endpoint and one USB BULK OUT endpoint (as well as the control endpoint.) This interface will be a full-speed (12-Mbps) USB enabling data transfer in and out.

The AOAM USB host has a set of string descriptors the Android OS is capable of reading. These strings are (user) associated with an Android OS application. The Android then uses these strings to automatically start the application when the hardware is connected. The FT311D is configured for one of its multiple interfaces via configuration inputs at power-up. Each configuration will supply the Android device with a unique set of string descriptors, therefore enabling different applications to run, depending on its setup.

The FT311D’s configuration determines whether each application will have access to several user interface APIs that are specific to each configuration.

The article goes on to examine the various interfaces in detail and to describe a number of demo projects, including a multimeter.

Many of Bachiochi's projects use printable ASCII text commands and replies. This enables a serial terminal to become a handy user I/O device. This current probe circuit outputs its measurements in ASCII-printable text.

Many of Bachiochi’s projects use printable ASCII text commands and replies. This enables a serial terminal to become a handy user I/O device. This current probe circuit outputs its measurements in ASCII-printable text.

Multimeters are great tools. They have portability that enables them to be brought to wherever a measurement must be made. An Android device has this same ability. Since applications can be written for these devices, they make a great portable application tool. Until the AOAM’s release, there was no way for these devices to be connected to any external circuitry and used as an effective tool.

I think FTDI has bridged this gap nicely. It provided a great interface chip that can be added to any circuit that will enable an Android device to serve as an effective user I/O device. I’ve used the chip to quickly interface with some technology to discover its potential or just test its abilities. But I’m sure you are already thinking about the other potential uses for this connection.

Bachiochi is curious to hear from readers about their own ideas.

If you think the AOAM has future potential, but you want to know what’s involved with writing Android applications for a specific purpose, send me an e-mail and I’ll add this to my list of future projects!

You can e-mail Bachiochi at [email protected] or post your comment here.

 

Scott Garman, Technical Evangelist

This article was a preview of an upcoming interview in the February issue of Circuit Cellar. The full interview is now available here.
Garman_web

Scott Garman is a Portland, OR-based Linux software engineer. Scott is very involved with the Yocto Project, an open-source collaboration that provides tools for the embedded Linux industry. Scott tells us about how he recently helped Intel launch MinnowBoard, the company’s first open-hardware SBC. The entire interview will be published in Circuit Cellar’s February issue.—Nan Price, Associate Editor

NAN: What is the Yocto Project?

 SCOTT: The Yocto Project is centered on the OpenEmbedded build system, which offers a tremendous amount of flexibility in how you can create embedded Linux distros. It gives you the ability to customize nearly every policy of your embedded Linux system.

I’ve developed training materials for new developers getting started with the Yocto Project, including “Getting Started with the Yocto Project—New Developer Screencast Tutorial.”

MinnowBoardWEB

Scott was involved with a MinnowBoard robotics and computer vision demo at LinuxCon Japan, May 2013.

NAN: Tell us about Intel’s recently introduced the MinnowBoard SBC.

SCOTT: The MinnowBoard is based on Intel’s Queens Bay platform, which pairs a Tunnel Creek Atom CPU (the E640 running at 1 GHz) with the Topcliff Platform controller hub. The board has 1 GB of RAM and includes PCI Express, which powers our SATA disk support and gigabit Ethernet. It’s an SBC that’s well suited for embedded applications that can use that extra CPU and especially I/O performance.

MinnowBoardOWI_web

Scott worked on a MinnowBoard demo built around an OWI Robotic Arm.

The MinnowBoard also has embedded bus standards including GPIO, I2C, SPI, and even CAN (used in automotive applications) support. We have an expansion connector on the board where we route these buses, as well as two lanes of PCI Express for custom high-speed I/O expansion.

NAN: What compelled Intel to make the MinnowBoard open hardware?

SCOTT: The main motivation for the MinnowBoard was to create an affordable Atom-based development platform for the Yocto Project. We also felt it was a great opportunity to try to release the board’s design as open hardware.