USB is Universal Serial Bus. If your question relates to a specific chip, please mention it in your question.
6
votes
2answers
364 views
What is the reason this USB battery charge circuit will not work without a diode?
I have a single cell, ~2100mAh rated Li-Ion battery. Something like 18650, I have taken it out from a laptop battery pack. I want to make a simple charging circuitry for it since I will use it in the ...
6
votes
1answer
628 views
TI Launchpad MSP430 on Serial in Linux
The MSP-EXP430G2 LaunchPad Experimenter Board User's Guide (Rev. C) in chapter 3.2 states:
The LaunchPad includes a pre-programmed MSP430G2553 device [...]
Press button P1.3 to switch the ...
6
votes
1answer
180 views
Is it possible to make a power auto-selector (ORing) with just a Diode and Mosfet?
I know there are ways to create a simple auto-selector using a mosfet and op-amp, or even simpler using just Diodes, but is it possible to have this work:
The mosfet is P-Channel so floating gate ...
6
votes
1answer
523 views
Understanding USB Inrush Current Requirements
In relation to a previous question, I'm trying to understand the USB 2.0 requirements for inrush current. I understand the basic idea, but a few details are still unclear to me. The specification ...
6
votes
1answer
169 views
Redpark cable for arduino, any alternative
I'm trying to interface my Arduino and iPod. If I use my Apple USB female connector and I buy a usb2serial cable ($5), can that combination work in place of this Redpark cable ($59!!)?
Redpark ...
5
votes
3answers
862 views
A simple on-circuit RS-232 to USB converter
I want to interface a PIC microcontroller (18f452) to a PC via the USB port. I learned that there is a USB class for serial communication so I will not have to write device drivers for it.
I want to ...
5
votes
6answers
2k views
Reverse engineering USB signals
Let's say there is a USB stick that is specifically for storing dates or days or some kind of arbitrary data. In order to access the data you must have the software.
Is there any way to analyze the ...
5
votes
3answers
2k views
Apple Desktop Bus (ADB) to USB Adapter
I have an old Apple keyboard that I would like to use but it uses the ADB bus instead of the newer USB bus. Griffin used to produce a product called the iMate which was an ADB-to-USB converter but ...
5
votes
4answers
594 views
Connectorless MicroUSB or miniUSB on PCB: Feasible?
This question extends upon "Connectorless USB on a PCB". Our requirements are for a smaller connector than standard USB, and also 5 leads instead of USB 1.0's 4. The connector will be used perhaps ...
5
votes
3answers
1k views
Best way of making a battery powered USB charger?
I recently made a USB charger that takes a 9V battery. I've noticed it doesn't work with a lot of devices though. It was very simple though, just a 5volt regulator hooked to a USB plug and 9V battery ...
5
votes
1answer
133 views
What does the USB bootloader do in the PIC microcontroller
I was wondering what does a boot-loader do, there is one USB Bootloader for the PIC micro-controller and I was wondering as to what its purpose is. How is it different from creating some HID device ...
5
votes
4answers
709 views
Advice for USB Sniffer
I am looking for a USB protocol analyzer and was wondering if anyone had any experience with one. So far, I am looking at an Internal Test Instruments and a Beagle USB 12. I only need to watch the ...
5
votes
2answers
27 views
How do I use a USB OTG cable to read a USB thumbdrive on Arduino Uno?
Is is possible to use a USB OTG (On-The-Go) cable hooked to the Arduino Uno's (or similar) USB connector to read a thumb drive or other device? If it is possible, what software would be needed?
5
votes
2answers
398 views
Testing an FTDI chip
I have an FTDI chip (reference manual here) that translates USB from a PC to an SPI channel connected to an FPGA. I would like to test that the communication path between the PC and the FPGA is ...
5
votes
2answers
586 views
Sensor Polling via USB-RS485 Serial Interface stuck at 16ms, even though it should be faster
I have a setup, connecting a Razor IMU sensor board, with a RS-485 Breakout board, to a USB-RS485 Serial Interface via USB-cable into my laptop. I run a software on the laptop (Max/MSP) that sends out ...
5
votes
1answer
414 views
DIY: hardware encrypted pendrive
I would like to build a hardware encrypted (at least AES-128) pen drive for myself. Which micro controller and which storage technology do you recommend?
I've been experimenting with a PIC32 and a 2GB ...
5
votes
2answers
760 views
RS232 vs USB CDC quality of service / should messages contain a checksum?
Does USB have a quality of service guarantee for data sent between my USB-CDC device and the USB host?
I know with traditional RS232 in a noisy situation (e.g. automotive diagnostic port) bad bits ...
5
votes
1answer
2k views
How to filter noise from ground?
I have an audio application scenario here. The Idea is to power a device (that later produces sound) with USB.
Unfortunately, I have massive static and what sounds like pink (Brownian) noise on GND. ...
5
votes
1answer
199 views
What's the easiest way to create a software-controlled 220V electricity interruptor?
As the title says, I'm looking for an easy way to interrupt a 220V electrical cable and to write a software that controls the interruption.
I imagine there are some kind of relays or contactors which ...
5
votes
3answers
3k views
Control robot with Android phone
Basically we're building a simple setup with an Arduino board and some motors. The Arduino with motor shield will control several servo motors and DC motors, and possibly talk to a few sensors. This ...
5
votes
2answers
641 views
Dual Role USB device on AVR
Is it possible to run both USB Host and USB Device controllers on top of an AVR (ATMega64)?
Specifically, what I'm looking for is to receive data from a usb keyboard, and simultaneously sending ...
5
votes
3answers
619 views
Problems with a RFID reader from SparkFun
I am hoping someone here can help me.
I am having trouble with a RFID kit I bought from SparkFun. I purchased the USB RFID (SEN-08852) with the RFID Reader ID-12 (SEN-08419) and some RFID cards.
...
5
votes
1answer
2k views
Is galvanic isolation of Hi-speed USB impossible?
I have a USB isolator which provides galvanic isolation of a USB device from my PC, but only works for low speed and full speed USB. I can't find any alternative electric isolators which do provide ...
5
votes
3answers
9k views
How can I fix an AVRdude not-in-sync error when programming Arduino via USB-to-serial cable?
I'm trying to build this Ambient lighting for PC. This worked flawlessly on my Arduino Uno. My next step was to make it using "Arduino on a breadboard". So I bought a blank ATmega328 chip and burned ...
5
votes
1answer
210 views
What is a USB transceiver?
I'm in the process of learning how USB works. What is a USB transceiver and how is it different from the PHY logic of a host controller?
5
votes
1answer
1k views
Arduino Duemilanove external power source with USB connected
Can Duemilanove USB interface be used for data transfer/programming when the board itself is connected to an external power source? (say, USB is not powerful enough)
What are the requirements for the ...
5
votes
1answer
110 views
If I change the chipset of a USB product, should I change idProduct or bcdDevice?
The product looks outwardly the same, with the same model number, but the USB brains have been completely replaced, and the circuitry's been modified to fit them.
The operating system needs to see ...
5
votes
1answer
967 views
Communication between Microchip PIC24F & Android device
I am working on Microchip with Android Application via Android USB framework.
Currently, I have written a while loop to generate the random number continually.
It is possible to retrieve the random ...
5
votes
2answers
1k views
Identifying a USB charging port without enumeration
Is there a low cost and reliable way to identify a USB charging port?
I plan to charge a device via the USB port. The USB Battery Charging Specification 1.1 allows 1.5A current draw when connected to ...
5
votes
2answers
242 views
How is this crystal / ferrite bead / ground shield connected?
This is part of the schematic for a TI TAS1020B USB Streaming Controller MCU that I don't quite understand. Obviously the shield connects to one end of the ferrite bead, but what else? Are the XTAL ...
4
votes
4answers
5k views
Are AA-to-USB Direct Chargers Safe?
I've found some Do-it-yourself guides to making a 4-AA battery usb charger, which are basically four AA batteries connected to a cut up usb cable:
...
4
votes
4answers
556 views
Use UART Tx as digital output?
Would it be possible to send a 5 V "true" signal from the Tx of a UART dongle? As if it were a digital output?
Here is the UART adapter I purchased.
4
votes
2answers
2k views
Why are these USB data lines conned to pull-up resistors?
I recently got a car lighter to USB adapter which I planned to use to charge my mobile phone. Unfortunately, the phone won't charge (and I know that the phone is capable of charging over USB port), so ...
4
votes
3answers
816 views
What happens if you charge a laptop using it's USB power?
To play a joke on this question, we came up with the following image on the Super User Chat.
Of course this will not work, but now my question is:
What happens if you charge a laptop using it's ...
4
votes
5answers
425 views
USB micro B receptacle has 6 mounting tabs. How many do I actually need to ground?
This USB micro B has 6 mounting tabs. If I ground none or only 1 of them, will it ruin the signal? There is a pad for the signal ground that is separate from the mounting tabs.
Fyi USB 2.0 has a max ...
4
votes
5answers
750 views
Weird Toyota Prius and USB behavior
My brother in law bought a Prius recently. He's experiencing something strange with his iPod.
If he has his iPod plugged in via the USB cable to the Prius, everytime he starts up his car, it resets ...
4
votes
3answers
122 views
Digital Isolation comparison
I am currently using ADuM4160 by Analog Devices as a USB isolator.
However, this part is EXPENSIVE. I was wondering if anyone thinks it can be replaced with ADuM2200.
Any reason why this wouldn't ...
4
votes
3answers
441 views
Proper behavior for USB and +5V
I have a batch of Sanguino 1.3a RepRap boards, with the following "bug" listed:
The USB 5V VBUS is connected to the output of the 5V regulator. This is bad for the regulator and bad for the PC. ...
4
votes
4answers
2k views
Is it possible to use a Microchip PIC32 as a USB host and device at the same time?
I'm designing a system and maybe (if I don't find better alternatives) I will need to use a PIC32 as a handler in between two USB devices and a host. My plan is to use the PIC32 to hide the devices, ...
4
votes
3answers
528 views
USB descriptor (LUFA)
I'm trying to jump in the USB world with LUFA on a Teensy dev board, but I'm stuck in the understanding of the descriptors.
Currently I'm trying to add one button to the joystick demo without sucess. ...
4
votes
1answer
256 views
Does a self-powered USB device have to connect to VCC from the host port?
A self-powered USB peripheral provides its own power, so is it okay to connect just D+, D- and GND to the host port, or do you always have to connect +5V as well, then wait for the negotiation phase ...
4
votes
3answers
340 views
Using lots of slide potentiometer for computer control
I want to mount a bunch (say 16+) slide potentiometers in a long project box (or other housing that can sit on a desk) that I can use to interact with software on my computer, specifically lighting ...
4
votes
2answers
937 views
Can I get the chip or electronic kit of a USB keyboard alone whithout the plastic case?
first of all, understand that I have a very basic knowledge of electronics.
I have a Commodore 64 case and I want to turn it into a USB keyboard.
My approach would be taking a keyboard appart and ...
4
votes
3answers
198 views
Replacing a custom serial port connector with a Micro-USB 2 plug
I currently have a very fragile solution to connect my embedded device to a PC's serial port. This is mounted on the PCB: http://www.digikey.com/product-detail/en/DF13A-6P-1.25H(50)/H3384-ND/530681. ...
4
votes
2answers
388 views
Solving input noise
I built a very simple circuit so I could use my Bose headphones in the noisy server room without wasting batteries. I however feel silly that I did not know how noisy USB power was, thus the V(L) ...
4
votes
3answers
287 views
Sensing when micro USB power cable is unplugged from a smartphone (or other device)
I am looking to create a charging device that can provide 5v power to charge a smartphone (or other consumer electronics device) via micro USB. How would I go about making this charging device "aware" ...
4
votes
2answers
499 views
Problems with CDC Device Class
I'm using the Microchip 16-bit 28-pin starter board and the USB communication with the PC keeps breaking.
There are two microprocessors on the board. The application processor communicates to the USB ...
4
votes
1answer
362 views
Pogo Pins Schematic
I have a Galaxy Nexus phone which has pogo pins:
I have determined which pins are PWR and GND but I don't know what the third pin is. I assume it is for the dock feature of the phone so it knows ...
4
votes
1answer
384 views
Can an LPC1343 accept its initial program over USB?
The LPC13xx datasheet suggests some clock setup is necessary to use USB. Does the chip's built in boot loader make it possible to load the initial program over USB, or do the clock multipliers have to ...
4
votes
2answers
663 views
How does an FTDI chip work?
Someone asked me the other day how an FTDI USB to serial UART works, and I realized I didn't know. I looked at the datasheet for the FT232R and the block diagram didn't really help me. Can anyone ...
