by Publitek European Editors:
The Universal Serial Bus (USB) has become the connection scheme of choice for interconnecting different devices, many of them providing human interface support. Support for many different types of peripheral, which can be self- or bus-powered, calls for stringent protection for not just the target device, but also the bus itself.
For example, overcurrent protection for USB-powered devices is needed, both by standards such as UL60950, as well as by the USB specification itself. Also required is good electrostatic discharge (ESD) support to ensure that devices and the host are not adversely affected by the spikes caused by plugging in devices, or the user brushing against exposed pins in the USB connector. This article looks at the requirements for protecting the power and data lines in USB and covers devices such as the TE Circuit Protection Polyswitch, the STMicroelectronics USBLC6, the Texas Instruments TPDD4EUSB30, the NXP Semiconductors IP4234CZ6, the Littelfuse 1206L family and the Bourns MF families, among others.
Protecting USB From Power Surges – [Link]
USB OTG (On-The-Go) cable enables for example a simple connection of USB slave devices with a smartphone.
As we know, USB communications operates in such a way, that a Master (Host) device (usually a PC) controls all communication on the bus and Slave devices are only able to require attention. Slave devices are all common peripherials like printers, scanners, mouses, cameras, USB drives, mobile phones etc.
However, naturally there are situations, when we´d like to interconnect also devices, which usually operate in a Slave mode, for example a printer with a USB key, mobile phone with a USB key or with a keyboard etc. In this case we want one of the devices to act as a Master.
USB OTG solves this problem and enables to use a given USB device in a Master and in a Slave mode as well. A mode in which a device will operate is defined by wiring of an interconnecting cable itself (pin ID grounded or left floating). USB OTG is supported by many nowadays mobile devices, which can be switched to a Master mode by using of such a cable. That´s why, when you´ll use the USB-OTG cable, you can connect a USB drive, mouse, keyboard and other USB slave devices directly to your smartphone.
In case of interest, please contact us at firstname.lastname@example.org.
USB OTG – it´s better to be a master than a slave – [Link]
Steve Taranovich writes:
Mophie, a California-based designer and manufacturer of mobile intelligent devices and accessories, developed the juice pack, the first ever “Works with iPhone” portable battery case certified by Apple. I contacted the company via e-mail for its help clarifying this design as well as the component types. It has not yet responded, so I give you my educated guesses. EDN readers are encouraged to weigh in with their own thoughts and expertise.
Teardown: Cell-phone charger: nice idea done right – [Link]
asidorenk @ obddiag.net pointed us to this great little USB to Serial board:
This USB to serial (TTL) converter project is easy to build, it is simple and inexpensive. It is based on the PL2303SA USB to USART bridge from Prolific. The PL2303SA chip is not required an external crystal as the internal clock oscillator is continuously tuning up to USB bus frequency. Having chip in SO-8 packaging does not require special soldering skills to assemble the project. Please note: the TX and RX signal levels are 3.3 Volts.
USB to Serial Breakout Board for Prolific PL2303SA – [Link]
Zak Kemble builded a network monitor device able to show basic network statistics on a small LCD screen. He writes:
Whenever I want to see why a download is going a little slow or getting lag on an online game I’d have to log in to my routers web page or SSH in to see if its someone else in the house downloading/uploading, the net connection going wonky or just the server, this was a bit annoying to do, so I made this device to constantly show network statistics.
Bluetooth Net Monitor – [Link]
USB has established itself as the new standard for connectivity. That is why USB connectivity has become the “holy grail” of most embedded applications.
Well, let me get straight to the point. If you want to start developing projects with USB interface, you want to have the proper development tools. To have the tools that you need, you either have to buy or to do-it-yourself.
PIC18F4550 USB Development Board – [Link]
Alexander Holler writes: [via]
This page describes how you can use a small AVR device and a real-time clock (RTC) to build a hot-pluggable USB real-time clock (I’ve named it just usb-rtc), mainly for usage with ultra-low-cost hardware meant to be used with Linux.
The overall cost for one of those thingies I’m describing here is about 15€-20€, which isn’t really cheap. But I find it a valuable thingy because the result is a hot pluggable RTC, usable by almost any device which has USB. So it’s very likely you will use it for much longer than the device you currently want to build or search it for. In addition you might want to use it as a (hot pluggable) USB-I2C adapter too. The software I’m describing below already supports that.
How to build an USB real-time clock – [Link]
Brian Schmalz writes:
The UBW board is a small board that contains a Microchip PIC USB-capable microcontroller, headers to bring out all of the PICs signal lines (to a breadboard for example), only costs about $15-$20 to build and is powered from the USB connection.
UBW – USB Bit Whacker- inexpensive, simple input/output USB device – [Link]
After the success of small modules USB – I / O converters – PUSBIO with MCP2200 circuit intended for development and small batch production, which we introduced in Article MCP2200 USB module and I / O , and recently introduced software for USB I / O modules , now the company introduces new modules Pandatron with relays and optocouplers.
USB Relay – I/O modules – [Link]
Small Arduino compatible USB host board. Take control of your Android phone or other USB device in your next project.
This project began the day I saw the Google IO 2011 talk about the new Android Accessory Development Kit (ADK). I had never seen or used an Arduino before. I had written a few Android programs but something about being able to connect custom hardware to my phone inspired me to start this long trip down hardware lane. Specifically, I was inspired to create motorcycle navigation software knowing that I would be able to create a remote control for my phone that would allow me to control the software with gloved hands. I finished the navigation software a few months later, and it has been a great success. This board has allowed me to complete that project; I now have a remote control attached to my motorcycle.
Mini USB Host Microcontroller Board – Arduino Compatible – [Link]