USB is Universal Serial Bus. If your question relates to a specific chip, please mention it in your question.

learn more… | top users | synonyms

3
votes
1answer
37 views

STM32: Minimal USB bootloader circuit

I would like to use the builtin USB DFU bootloader of STM32F107 chip. My MCU is powered by the device, I don't need to use 5V from the USB. So far I have connected pins PA11, PA12 and GND directly to ...
0
votes
2answers
48 views

Constant DC 12V, 2A from USB 3.0, SATA, Molex or other common PSU cable?

I'm in the process of trying to power a simple LED strip lights, spec 12V, 2A, through a PC rather than transformer. So far, I am debating the first stage. After looking into USB 3.0, it can supply ...
1
vote
2answers
132 views

Do I need to use a capacitor to smooth voltage when powering a microcontroller with USB?

I'm trying to make a CNC machine with an Arduino Uno and 3 stepper motors. I plan on powering the Arduino with USB, but I need a 5v power supply for the 3 stepper motor microcontrollers. I couldn't ...
0
votes
2answers
136 views

Microcontroller to PC via USB - do I need to use isolation?

I want to connect my microcontroller (dsPIC33E) to a PC via USB. Since the particular microcontroller doesn't have a built-in hardware for the USB protocol, I have to use an external chip (e.g. ...
1
vote
0answers
35 views

Laptop webcam to usb cable [on hold]

I'm struggling to figure out what cables to hook to what to make my old webcam from my laptop work with a USB cable. I'm by no means an electrical engineer but I know the basics, I have a multimeter ...
0
votes
3answers
58 views

USB3 activity detection

Some USB hubs have status LED that shows activity. Let's say, I want to make a USB3 cable with status LED that would indicate any activity on the bus (changes of differential voltage). Is there a way ...
0
votes
1answer
53 views

How does a powerbank detect a connected USB device?

I got a powerbank powering a raspberry pi over the micro usb port of the raspi. The usb cable I use, has only to lines, Vcc and GND. When the powerbank is off due inactivity and I connect the ...
0
votes
1answer
71 views

What type of USB 2.0 connector is this?

I'm converting lots of USB card readers to be mounted directly on the tablets. One (relatively trivial) problem is that the readers come with long 6ft USB cables which I'd like to shorten to about 1ft ...
3
votes
1answer
63 views

Importance of baud rate in USB CDC

As I understand it, in PC-to-MCU communications over USB CDC, specifying a baud rate is only necessary when the MCU sends its received data to a UART. The baud rate is needed by the bridging device to ...
2
votes
2answers
84 views

Question about production of computer USB peripheral [closed]

I have a game controller. This controller have USB cable and when connected it is instantly recognized by the computer. I wanted to know what it made of so I opened the case and found "STM32F103C8T6" ...
0
votes
1answer
55 views

How do I correctly power a USB 2.0 while decoupled from signal?

I'm building a switch that will power on / off a bunch of USB 2.0 ports. In order to avoid overloading the USB hubs (as has been an issue in the past) I would like to power and switch my peripheral ...
0
votes
1answer
50 views

arduino pc communication

I wanted to ask what communication protocol arduino boards use exactly to communicate with pc? How can the serial monitor work on such high baud rates through usb? Will it be possible for using a ...
2
votes
1answer
59 views

How to find connections on board? - DIY Keyboard from Old Laptop

I have a project that I have hit a wall on. I need your guidance! I need to find the spots on the board for the 4 USB connections. The attached photo is of the board. There are 4 connections I ...
1
vote
1answer
60 views

What would be the proper way to wire a female-to-female USB connector

These are really cheap, I know. But I would like to make my own with two USB extension cables. My question is, after stripping off the 2 cables, do I wire red to red, white to white, and so on? My ...
0
votes
1answer
45 views

USB data detection [closed]

I am new to USB communication. I am studying the USB communication and protocol. I have always wondered about how USB devices actually communicate. I have a microcontroller with USB peripheral. I am ...
1
vote
1answer
15 views

Read USB Input on Android from IR sensor

A mainstream IR sensor has 3 pinouts: Vcc: 5V power GND: Reference ground Vo: Analog/Digital voltage output One can power the sensor using phone's mini USB's Vbus and GND (Can one?). Can one then ...
0
votes
2answers
50 views

USB OTG with occasional charging

I'd like to use a mobile phone together with a barcode scanner as a poor-man's version of a computerised barcode scanner, something like this: http://www.thebarcodewarehouse.co.uk/pdas-and-handheld-...
0
votes
1answer
20 views

How does a Dual-Port Wall Charger distribute Amperage output?

I recently bought a Dual-Port Wall Charger that has a '3.4A total output'. Assuming the device(s) plugged in are individually capable of charging at 3.4A, is this specifying that a single device ...
0
votes
1answer
40 views

Usb battery charging

I am designing a system which has a mcu (with usb peripheral). The whole system is powered by a 18650 Li ion battery. Now, imagine I am charging the battery by plugging the usb to a computer usb ...
0
votes
0answers
6 views

Combining multiple cables to increase current? (laptop charger) [migrated]

I'm looking to use a simple USB power bank as a portable charger for my laptop (just to get a little extra boost if the battery starts running low at an inopportune time). My plan is to use something ...
-1
votes
1answer
56 views

What is the maximum length i can choose for a USB cable made up of CAT6 shielded cable? [closed]

After frequent research over internet I found that USB can be extended beyond standard USB length limit of 5 meters. There are few methods such as USB hubs and USB Active repeater cables that allow ...
1
vote
1answer
15 views

USB3.0 Shield connection

In the below image for Amphenol GSB343K33HR, do the 4 rectangular pads in the center of the image signify Shield connections?
0
votes
1answer
41 views

USB CDC (VCP/UART) optional endpoint

I'm developing an USB application for a STM32 MCU. For now I have 2 interfaces for CCID classes and I want to add another for a Virtual COM Port. On a STM32F4, The limit of IN endpoint in FullSpeed ...
-4
votes
2answers
102 views

Can I splice a USB serial (with chip) directly onto a VGA male adapter to make a USB-to-DB9 serial cable? [closed]

I have quite a few older USB-to-whatever serial cables, and I found myself needing one that goes to DB9 for an old router... Is there any reason not to wire it to a VGA male adapter, which would (...
0
votes
0answers
13 views

Raspi + usb drive on external power supply

I am about to connect Raspi with usb drive. Raspi is powered from an old laptop 12V 5A supply through step-down 12/5V 10A converter. My question is this - If I connect USB drive power wires (5V, GND) ...
4
votes
0answers
83 views

Why aren't PCB mounted male mini USB connector parts common?

I'm looking to build a USB device that plugs directly into a mini USB OTG port - similar to those USB flash drives that can plug directly into smartphones with OTG-enabled micro USB ports. I was ...
0
votes
1answer
50 views

USB & 12V-Power-Supply simultaneously - Diode?

I'm currently designing a (fairly easy) circuit, which is powered by an ordinary 12V Power Supply. To flash the embedded µC and/or get debugging output, I use an onboard USB-UART-Interface. To make ...
0
votes
1answer
106 views

Plugging in USB device shorts out USB hub

My device is 12V DC and takes a maximum to 1.08 Amps. The cable is split where one end goes into power and the other end goes into USB. Works: Plug device power into 120V AC adapter which converts ...
0
votes
0answers
30 views

DC-DC step up and step down converter for a solar panel

I have a 1W solar panel that will output about from 0 to 7V (7V in full sun). I want to power up a small USB gadget with it. I need a device that is a step up converter when panel's voltage is under ...
0
votes
1answer
78 views

To use Power banks and DC-DC step up Converter to make Electric Bicycle battery Pack

Summary of the whole project I have a small project in mind, just want to find out is this a possible way to make a useful power pack rather then use this normal way [![enter image description ...
0
votes
0answers
41 views

Populating a list of connected ATMEGAs

I'm building some switchgear. Currently building a GUI to control an unknown number of PCBs based around the infamous ATMEGA328P, via a FT232R to the UART of the MCU. The current way of populating a ...
4
votes
2answers
2k views

Accidentally knocked a capacitor off a laptop motherboard seemingly related to USB

I accidentally knocked off a capacitor from my laptop motherboard (Lenovo Thinkpad S540, VIUS6 LA-A171P board). According to the circuit diagram, this capacitor (C2434) was something to do with the ...
0
votes
0answers
33 views

Problem when programming Atmel ATmega16U4 using USB

I'm having a problem when I'm programming the ATmega16U4 through USB port. I designed the PCB, but I will assume the hardware connections are good. It is because when I connect the chip to the ...
0
votes
2answers
93 views

USB, UART, SPI difference and usage? [closed]

I am trying to enabling an embedded system built around Intel D1000 MCU. I am mainly from a software background and just starting to catch up with some hardware knowledge. I am trying to build ...
4
votes
1answer
237 views

Use ATX power source to power Raspberry Pi

I'm setting up several Raspberry Pi's and Arduinos connected together, and I'm looking for a way to power them. Would it be possible to adapt an ATX stock power source with female USB plugs using the ...
0
votes
0answers
73 views

How do I build an interface between MicroBlaze and the FTDI FT600

I would like to implement USB 3.0 communication (instead of UART) with a custom FPGA board using Microblaze. I have already testing basic communication functionality in verilog, writing and reading ...
0
votes
0answers
58 views

Atmel ARM, USB, and an SD Card as a MSD?

I'm currently trying to run the SAM L21 as both a CDC and an MSD over USB. Thankfully there is example code here to get me started. I can move files into the on-board ram just like any other storage ...
-1
votes
1answer
92 views

How to capture USB data on the oscilloscope?

Using 2 channel oscilloscope (BK precision 2542B), channel 1 trigger on the triggered signal, channel 2 is on the Data+ of the USB port. After sending the triggered signal to the bar code scanner, I ...
0
votes
3answers
73 views

USB cables combining shield and power ground conductor

I see a lot of USB "charging" cables on the market with cutaways showing two small data conductors, one large power conductor, and shield. The implication is that power is conducted in the shield. ...
1
vote
0answers
22 views

Agilent 4155C/4156C Saving spreadsheet data directly to computer

I am using a Agilent 4155C Semiconductor Parameter Analyzer. Does anyone know how to save spreadsheet data using SCPI or FLEX commands directly to the computer instead of to a floppy (diskette) disk? ...
1
vote
3answers
70 views

switching 3A/5V with an optocoupler [closed]

I am planning to switch the 5V line to a USB load. I have being going around different suppliers looking for an optocoupler that can handle 3A at 5V. I have seen a few, but upon looking at the ...
0
votes
1answer
82 views

BeagleBone Black won't power up from USB

I have been successfully using BBB powered from the USB adapter until now. I had to do some restart, and then the board won't power up (the PWR led blinks once ...
1
vote
2answers
104 views

16 separate lines via USB

So let me start apologizing if the question doesn't make any sense at all, I'm a total noob and I haven't quite grasped most of the concepts yet. I have designed this small visual indicator, which ...
3
votes
3answers
157 views

What is the source of this shape on my USB eye diagram?

I have designed a USB device around an STM32F105. It is USB 2.0 Full Speed CDC device configured as a Virtual COM Port using ST's USB Library. It uses the STM32's built-in PHY, and runs at 12 Mbps. ...
0
votes
1answer
54 views

Homemade car socket USB charger - picking proper capacitors [duplicate]

So, I decided to make my own USB charger to use it in a car (even though I got it from China 2pcs for 1.4USD). I've started simple as possible, with using only 7805. Well, the effect was reached - my ...
0
votes
0answers
22 views

Mircro USB3.0 Mixing external 5V-Ground with the rest

So, my friend has a laptop whose only USB connection, a 10-pin micro USB3.0 connector has a broken VBUS (+5V) connector. I'm thinking to make an adapter where I can plug in a USB charger for +5V and ...
-1
votes
1answer
68 views

Ground my body to DC (USB) [closed]

Does grounding body to DC power source makes sense, to get rid of any electrostatic(?) charges from my skin/body ? In my new house, when I'm standing on the floor, connect voltage meter (AC) and ...
0
votes
1answer
67 views

My printer injects hum into my USB ports [closed]

I have a Brother HL-L2305 laser printer. I love it. I also have a pair of KRK Rokit 6 G3 speakers that I run off of an MBox 3. Every time I plug the printer into any USB port, hub or not, a loud hum ...
0
votes
2answers
92 views

How does a USB Hub work?

I know google's answer and wikipedia's answer for the above question. But I have a more specific question on hand. USB hubs have many incoming and port and just one outgoing port, I am able to use ...
3
votes
1answer
105 views

Why does usb have start of frame packets?

I'm developing some high-speed USB firmware for the STM32F746VG, and on page 1411 (under section 37.16.3, step 2), it tells me that I should enable start of frame interrupts. I know that usb hosts ...