Cheap low-speed dual channel PC/USB oscilloscope with STM32F3 microcontroller.
Miniscope v2d is based on STM32F303CBT6 microcontroller – LQFP48 device from STM32F3 family featuring:
- 32 kB RAM on data bus
- 8 kB RAM on instruction bus
- 128 kB FLASH memory
- USB device (full speed)
- 4 fast and flexible ADCs
- 12-bit DAC with two output channels
- 4 opamps that can work in PGA mode
- ROM bootloader with USB DFU option available
STM32F303-based low-speed PC/USB oscilloscope project – miniscope v2d - [Link]
Integrated circuit FT232R is becoming legendary and we bring you another example of FTDI USB chips usage.
In praxis we often face a requirement to communicate with devices, which have serial ports RS232, RS422 and RS485. As many devices – mainly notebooks, already usually don´t have these ports, it is necessary to use a converter to convert serial port to USB.
Company ComErgon, s.r.o. is long-term dedicated to development and production of such converters. ComErgon has in its offer models for RS232, RS422 a RS485 interfaces. USB to RS422 and RS485 converters are produced with a 1kV galvanic isolation, as lines on the RS422 and RS485 side can be lead even on long distances and an eventual overvoltage could be able to damage end devices. Version RS232-USB is available with galvanic isolation but also without isolation.
More detailed information and technical specification of these converters can be found at website of company ComErgon.
Company ComErgon focuses on development and production of converters for RS232, RS422, RS485, RS422/RS485 repeaters, serial to Ethernet interface modules, GPRS, Fiber Optic, 433MHz, current loop and other.
Customer solution: Trouble-free RS232, RS422, RS485 to USB conversion - [Link]
New USB chip from FTDI supports the Android open accessory mode, what enables a straightforward connectivity of USB devices and saves a battery of an Android device.
To connect a device to a smartphone (tablet,…) or other Android OS device via a USB is at the time possible in 2 ways – by means of a USB OTG (On The Go) or via a so called „Android open Accessory“ mode. USB OTG was introduced to you in the article – USB OTG – rather to be a master than a slave. USB OTG functions very well with many external devices but this method has one substantial requirement – your smartphone must recognize a given external device – it must have a suitable driver installed (similarly like at PC). The problem is, that for many USB devices you mast a driver to your Android device, what can be problematic from various reasons – absence of a suitable driver, “locked” system (limited access rights) loss of warranty on an Android device, ….
As a solution of these problems the Android Open Accessory Mode arised, when the role changes upside down and an Android device communicates in the USB device (Slave) slave. It means that the Host role takes an external device, while eliminating a need to develop drivers and guarantees a trouble-free communication. It means that this mode is very suitable for development of new devices intended for operation with Android devices. At the same time, the USB bus is powered from a Host device at this mode, what saves the battery of an Android device. Usually an application in a given OS uses drivers to communicate with a USB device. However in this case no drivers are required – an Android device reads a set of strings describing a given device (producer, model, URL address …) what is able to automatically start an application after connection of a given device. USB communication itself uses 2 endpoints for input and output (Bulk IN and Bulk OUT). That´s why an Open Accessory mode is suitable for all kinds of devices – data producing (sensors, probes,…) but also for data receiving (printers, robots, …).
FT311D brings this solution into reality and functions as a bridge between an Android device and various serial interfaces. It is possible to choose from up to 6 interfaces what suits to perhaps all nowadays devices – UART, PWM, SPI Master, SPI Slave, GPIOS, I2C Master. A great advantage of FT311D is, that the producer – company FTDI provides an extensive development support, including the UMFT311EV development board, code examples and demo applications.
Detailed information will provide you the FT311 datasheet, FT311 WP_001 and FT311D Android programmer guide. Further files can be found on the http://www.ftdichip.com/Android.htm
In case of interest, please contact us at email@example.com.
FT311 – USB communication with Android devices without drivers - [Link]
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]