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Questions tagged [usb]

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

0
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2answers
39 views

Protecting USB hub from ESD

I am working with a robot that uses USB (not by choice lol) in a very static-prone environment, and I'm having problems with ESD locking up my USB hub. I found an "Industrial" USB hub that claims it ...
1
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3answers
63 views

How to solder on a new USB plug/connector

I bought a USB WiFi card, but then the metal part broke and I had to take it off. I only have the board now and it is too small to fit into a USB port. Where can I find a new USB head/plug (the silver ...
12
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5answers
3k views

Why does USB only use 2 lines for RX, TX instead of multiple data lines? [duplicate]

Wouldn't it be faster if there were multiple data lines (say 8) to transmit/receive data (say sequential bytes) instead of using a single line to transmit sequential bits?
0
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0answers
101 views

RS485 7 Pin to USB, Is it possible? [on hold]

I have a Pump with RS485 via 7 Pins, and also have a convertor with 5 Inputs, Is it possible to connect together and plug to PC via USB? As comment We can tell on 7 wires: Black = E-C ground Yellow =...
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1answer
101 views

Why weren't all usb ports type c /symmetric from the beginning? [closed]

Did it really take them so long to think about a symmetric port?
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2answers
32 views

Read temperature sensor from microcontroller to Android application (via microUSB)

I'm working on a concept for a project, and I'm having difficulty determining whether this application is possible. I will have some misc. microcontroller with an attached temperature sensor, and ...
1
vote
1answer
36 views

MSP430 USB Module and Baud Rate Detection

I am working on a project which uses the USB module integrated into the MSP430F5529, specifically using the MSP-EXP430F5529LP development board from TI. I am using the USB API provided in MSPWare. ...
0
votes
1answer
55 views

USB 3.1 AC Coupling Capacitor Implementation

How should the AC coupling should be implemented when connecting a USB 3.1 hub to a USB Type-C connector through a MUX. Is it: Both sides of each MUX. On the switched output of each MUX. On the ...
1
vote
1answer
40 views

USB UART Bridge with capability of handling fast charge VBus

I am trying to design a charging circuit which support QuickCharge but also I want to add USB-UART bridge to communicate with on board MCU. How can I establish voltage level safe communication ...
0
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1answer
33 views

USB connection new car stereo 5 wires to 4 (schematics included)

I am replacing the stock stereo in my 2015 Nissan Leaf S. In the center console is a USB port which was connected to the head unit. I'd like that port to continue to work with my new stereo. The ...
1
vote
1answer
26 views

USB hub and upstream/downstream speeds

I am designing a USB hub that has a 2.0 upstream connection (pc is only 2.0). To one of the downstream ports I am connecting a Ethernet to USB IC capable of USB3.0 speed and Gb ethernet. My question ...
0
votes
1answer
43 views

Issues with designing ground plane for switching relays in high noise environment

I am designing a PC Controlled 8 channel Relay using AVR microcontroller. Here, the relays are on the right side of the board and are controlled by the AVR micro on the left side. The eight TTL ...
1
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1answer
54 views

Why is the usb shield always tied to ground (GND pin)?

The shielding on a cable is to avoid interference from the outside world however it is always tied directly to the GND pin. Not inside the cable itself but inside a device. Every single device I take ...
0
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3answers
104 views

Unrecognized usb3.0 device using non-standard connector

I Have two PCBs,pin out define as follows ,the host pcb is A connector,and the device pcb is B connector. I use the 1.25pitch connectors&USB3.0 cable to connect two boards,but the host board ...
0
votes
1answer
48 views

Type A female USB port [closed]

I ordered a Type A USB port because I thought all Type A USB ports were the same, come to find out after taking the laptop completely apart that the 4 prong 2.0 USB port I ordered was way different ...
1
vote
2answers
114 views

Trouble with PCB design for USB3 connections

I'm struggling with making a USB3 connection work. The PCB needs two USB3-A female receptacle, to play sort of a "man-in-the-middle" role. I cannot provide much detail, since it is part of an ...
2
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2answers
1k views

Arduino and USB, how it works?

After purchasing an Arduino board (UNO) I decided not to use Arduino IDE as it lacked some features and all libraries are written in C++. I am coding with C. One thing that I really do miss is a ...
1
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2answers
94 views

Are standard USB connectors (Standard / Mini / Micro) Impedance controlled?

Are standard USB connectors Impedance controlled? Do they follow differential characteristic impedance of 90 Ohm for DM & DP lines? Does standard Type A, Mini / Micro - USB Type follow same ...
1
vote
1answer
55 views

How to determine bandwidth available at USB ports

I am considering a mini-itx single board computer for a project that makes heavy use of USB. I want to ensure that certain USB devices have enough bandwidth. For example I have a data acquisition ...
0
votes
1answer
65 views

help figuring out how to replace/repair this component

The micro-USB jack in this board is broken and I was trying to figure out how to replace this entire thing. The micro-USB is for power/charging and the bigger USB has unknown functionality that we've ...
4
votes
1answer
85 views

USB Camera to GPU Memory Directly

There may be several points in this question which may not make sense to a knowledgeable person, so I do thank you for your understanding in advance. For a computer vision project I wish to process ...
0
votes
1answer
29 views

Problem with using USB HOST HS example

I am working with USB HS Host in MSC class with STM32F407 MCU. I want to write to the memory cells of a flash drive using usb. (It doesn't matter for me to write with a standard like FatFs, I just ...
0
votes
1answer
50 views

Taking Quizbowl buzzers and connecting to a computer

Recently I Bought quizbowl buzzers from buzzersystems.com and the buzzers i received use an rca cable. If you did not know basically, when you click a button, it sends a signal to a box which ...
0
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3answers
142 views

How does a USB to DB25 parallel cable work? [closed]

I've been searching for technical information to explain how this works but can't find any info, pinouts, technical reference of any form. I want to program a parallel port to control a USB device ...
1
vote
1answer
42 views

Driving power + USB over cartridge connector [closed]

I hack old hardware (mostly microcomputers) by putting new insides in them, but I still consider myself a newbie when it comes to electrical engineering, so please bear with me, because this question ...
1
vote
2answers
57 views

USB power split

I want to connect 2 devices to one USB. Device #1 is a small audio DAC with USB A male connector. Device #2 needs only power. The question is, do I need to do a special separation for that or this ...
1
vote
1answer
37 views

How to charge a battery when the charging socket is broken? [closed]

First of all I'll explain my situation: I own a Bluetooth speaker, more precisely this one: http://www.leicke.eu/en/products/EP18108 Due to my clumsy hands it fell while the USB cable was connected ...
0
votes
1answer
55 views

USB 3.0 Length matching in PCB Layout

I'm doing PCB layout for a USB 3.0 connection and I'm curious about if there's a length match requirement between the unidirectional super speed pairs and the bidirectional high speed pair. This isn'...
0
votes
1answer
28 views

uploading sketch using mcp2221 to Atmel Mega1284P

Hi I am unable to upload sketch to Atmel mega1284p using a mcp2221 usb to uart converter IC. I have a simple code prints "message received" It works to program the Mega1284p using arduino nano as ISP....
1
vote
1answer
55 views

USB 3.1 Type-A Legacy Connector to USB 3.1 Type-C

I am unsure of how to design for the following arrangement, any input would be greatly appreciated: Computer [USB Type-A Connector] -> USB Type-A to USB Type-C Cable -> Custom PCB [USB Type-C ...
0
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0answers
33 views

USB Lightning Cable Reads 2.3 Volts

An Anker USB lightning cable was salvaged \ severed so that it could be used to power a breadboard with 5V. The photo shows that the wires are not black \ red and is connected to a 5V power source....
0
votes
1answer
89 views

STM32F103 USB CDC [closed]

I have a strange problem with USB CDC mode in STM32F103. I have designed PCB with STM32F103 microcontroller and an accelerometer which streams data through USB to PC. I have used STM32CubeMX wizard. ...
1
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2answers
63 views

Creating a vibration device based on bass in audio [closed]

First, I'll admit that I haven't done any real electrical engineering in years so I'm quite rusty. But here's a fun project to contemplate: I'm building a device that "rumbles" with the bass in the ...
1
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1answer
58 views

What are the leading bytes before the USB setup

While tracing the USB using a Beagle 12, I am sometimes finding bytes prior to the transaction start. It is not the 8/32 bit SYNC, it does not start with a PID (e.g. 0x12 is 00010010b and a PID is ...
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0answers
41 views

Isolation for USB 2.0 High Speed (480 Mbps) [duplicate]

The fastest isolators available a a reasonable cost are 150 Mbps per channel. High Speed USB has a data rate of 480 Mbps. So how do you isolate a HS USB? The first thing that comes to mind is to ...
0
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0answers
34 views

PWM on Dedicated Charging Ports

So, after reading the post about how to design a 2A phone charger, I decided to give it a try. But I don't feel like using resistor dividers, I like something more digital. I wonder if I can bias the ...
1
vote
1answer
78 views

Why do USB data cables have 5 wires, what is the use of shielding wire?

I have always been curious about the 5th wire(aka shield wire) in USB cables. What is its purpose? Does it anyhow affect charging speed for mobiles or data transfer? I do know that it carries the ...
0
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2answers
116 views

Most cost effective way to test USB 3.0 eye diagrams

I saw this question addressing testing USB 2, but I was wondering what the most cost effective way to test USB 3.0 superspeed was. Obviously the frequencies are far higher (multiple GHz), so the test ...
0
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2answers
88 views

Unidirectional vs Bidirectional TVS on USB devices

Is there a reason to use unidirectional TVS diodes over bidirectional TVS on USB circuit protection apart from cheaper cost? As USB is a DC powered circuit, I feel like unidirectional TVS diode (such ...
0
votes
1answer
59 views

5V USB and 110VAC proper procedure?

My apologies in advance if this has already been asked I have a MCU (esp8266 or esp32) which will primarily live off mains power with transformer 110VAC -> DC 3.3V Occasionally USB is plugged into ...
0
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2answers
66 views

USB hub circuit

I have a custom made USB hub with 4 USB ports. It gets 5V max 500mA. Below is the datasheet for the hub chip http://minipcsale.ru/images/Minix-Neo-X8-h/GL852G.pdf now my question is If i connect 4 ...
0
votes
2answers
301 views

How can I modify a USB cable with a voltage-divider to provide 3V? [duplicate]

I want to power a small device, that normally uses 4 AA/R6 batteries arranged in 2 pairs (so the device requires about 3V DC and drains probably 100mA or less). Is it possible to cut an old USB ...
2
votes
0answers
68 views

DIY 4S Li-Ion battery pack

I am in need of some help designing my battery pack. I have a few concerns, mostly around charging. My plans consist of using a microUSB boost converter to bring the voltage to 16.8V for charging. ...
0
votes
1answer
33 views

HID “report descriptor” includes set/get features?

After reading about HID report descriptor, it seems that it only includes "input report". http://www.rennes.supelec.fr/ren/fi/elec/docs/usb/hid1_11.pdf But what about get/set features ? Why it is ...
3
votes
2answers
1k views

USB Chain Connections

I have two questions related with the USB connections on a pcb: 1- Is it possible to connect D+ line between 2 devices and 1 host? something like SPI fashion where MISO and MOSI lines are shared ...
0
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1answer
16 views

Variations in RFID USB Serial reader detection distance by connected device

I have a RFID reader that sends the TAG information over USB serial. I have had some troubles with it in a product where the detection success rate changes alot depending on what the USB RFID tag is ...
2
votes
1answer
99 views

USB-C / USB 3.0 alternate mode as low speed serial port

I want to make a device which can be connected either to a PC with an USB 2.0 connection or to another identical device and have a serial connection. This should be detected acutomatically and I want ...
3
votes
1answer
82 views

Are all the pins from a USB3.0 micro-B connector necessary

I'm designing a system that has a camera (Ximea: MQ042RG-CM) that uses a female USB3.0 micro-B connector. I could connect to my computer through a male end, but I want to minimize the number of ...
1
vote
2answers
64 views

VHDL: ADC to USB Buffering using Fifo

I am trying to understand what is the correct way of doing such application, so please do not ask for complete code because each component is working fine on its own. I am struggling in the way of ...
1
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2answers
182 views

USB power cleaning

I may have posed this question before, but it bares repeating. Today I put a scope on the USB output of one of those universal travel power converters. I was appalled. It was noisy as all get out. I ...