Questions tagged [usb]

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

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2answers
67 views

max. output current of USB port and damage to the USB device

A USB host can generate up to 500mA. Would it mean that the host device is never damaged by a short circuit on a USB guest device? When I play with Arduino, I sometimes see that my PC freezes. The ...
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1answer
67 views

Is USB host always protected from reverse current?

Does the USB specifications require that USB ports of a USB Host device are always protected from reverse current? If one connects a USB host to a different USB host for some reason, is it natural ...
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1answer
223 views

STM32F103C8T6 fake? [closed]

I have a curious problem: Prequel: I "designed" a clone of the Black Magic Probe v2.1, which I like a lot but has IMHO some shortcomings (e.g. the 1.27mm-pitch connector to name just one). I got a ...
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1answer
90 views

Power bank multiple output currents

I've been working on a simple power bank project that's been built using Li-ion batteries, the batteries are rated 3.3 V. I've implemented a charge controller which can efficiently charge the power ...
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1answer
53 views

Is there a good/standard way to find the equivalent to this part but for a different connector?

I'm looking for a USB connector part. I've found one part that has the right mount, but it has the wrong USB connector (in this case it is a mini USB). Is there a good way for me to look for a part ...
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1answer
79 views

Stop USB Device from Passing Power to Machine

Summary: The RC Controller that I'm using for a PC game to practice flying quads is, I suspect, passing power through the line and causing my machine to shut down. What I'd Like To Do: Change ...
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1answer
29 views

Powering dual 5VDC, 2.4A USB ports via a switch in vehicle

I have an illuminated 2 port usb charger that plugs into a cigarette lighter/accessory socket in a car. The face of the charger is flat and sits flush when inserted into the cigarette lighter/...
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2answers
150 views

Bus-powered non-USB device (like fan,lamp) USB pin arrangement to getting highest power from USB host

Bus powered means device that only use Vbus of USB for it's power supply. I want to use micro USB as my board power supply. The is designed to take 600mA by 3.3v regulator. But I just don't know how ...
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1answer
85 views

Are there 5V battery packs available without a boost converter? [closed]

Looking for a 5V portable power source without switching or conversion noise.
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1answer
604 views

Getting MSP430 USB Driver Signed By Microsoft

I am developing a product which utilizes an MSP430 microcontroller with a built-in USB module. I obtained a PID from Texas Instruments and used their tools to generate the descriptors, as well as a ....
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2answers
92 views

Divide RS-485 Simply without switch

I have an RS-485 input / output from a solar charge controller (SCC) and would like to read the output in two locations, while maintaining its input from one, or hopefully both of those locations (see ...
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1answer
335 views

Small microcontroller with USB host peripheral [closed]

I'm trying to find microcontroller with low pin coutn that has USB host capabilities. I know this can be done with big PIC24 or PIC33 microcontrollers, but I wonder if there are others chips that ...
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0answers
39 views

Voltage Regulator with Reverse Voltage

I have designed a simple PCB circuit board that is powered by either the 5V from a USB, or if a battery is plugged in, powered from a 3.3V and 5V regulator. I am no expert in electronics, but have ...
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2answers
88 views

What can be said about the dB attenuation for this ferrite bead from its impedance graph?

If I use this ferrite bead for a USB cable, what can be said about the noise attenuation for 1 MHz and 10 MHz. The plot only shows the impedance versus frequency, whereas I would like to see the ...
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0answers
69 views

Challenges to DIY a USB QC 3.0 charger for a DJI Mavic Pro @ 13V?

One of the big pain points with all of the DJI Mavic Pro drones is that they do not charge via USB. In order to charge the batteries you have to buy an AC-DC adapter which adds a good amount of extra ...
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2answers
130 views

A question about usage of common mode chokes for USB cables

There are ferrite chokes, rings to suppress CM EMI and they are also used for USB cables as shown in below example: But isn't USB differential signaling type of transmission? That means to be the ...
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1answer
40 views

Microbit - Control an LED that is powered externally

this may be a bit of a noob question but I am trying to make a motion activated light with my Microbit. I have a 1W superbright LED and its clear the Microbit won't supply the current needed for this ...
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3answers
123 views

Am I exceeding current limits for the USB port? [closed]

This USB 2.0 hub gets the power from one this PC's one of USB port. The hub is connected to six of this USB DAQ devices. The hub both communicates and powers the six DAQ boards.The power for the DAQ ...
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1answer
193 views

How to make a system with USB 3.0 slave that provides data to an FPGA? [closed]

I consider making a system with USB 3.0 slave interface that provides data to an FPGA, where the connection should allow full utilization of the available USB 3.0 speed. What external components are ...
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1answer
73 views

Is the following USB connection possible: Host USB to converted to serial (FTDI) and then converted back to USB (FTDI)

I am trying to connect a host USB device on one board to an endpoint USB device on another board, but I am required to send the link between the two devices as a serial (UART) connection between the ...
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2answers
95 views

AC voltage on the outside surface of micro USB charger cable

My micro USB mobile charge cable is having about 98V AC voltage on the outside surface. (PFA measurement image. The black probe is connected to the Power socket Ground port. I could not take the whole ...
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3answers
292 views

How critical is PCB layout for USB Full-Speed?

I have designed a custom USB hub PCB with a TI TUSB2046(USB Full-Spped hub). Considering 12Mbps data rate, how critical are the layout constraints for the USB data lines? I did not follow the exact ...
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1answer
74 views

Switching a USB HDD on and off

I have a PC which I backup to an external USB3 HDD drive from time to time, I manually connect the drive whenever I "remember" to do the offline backup. I don't want to keep it connected all the time ...
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2answers
200 views

USB Softcore for FPGA : Extra resistor on FPGA transmitter pin

Have anyone used this USB softcore before ? Why do we need extra resistance on the tx pin ONLY ? Whichever pins you transmit on need to have resistors after them. The exact values will depend ...
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0answers
25 views

USB wall charger current question [duplicate]

I have a USB wall charger with this text on it: INPUT: 100-240V 50/60Hz 0.5A OUTPUT: 5.2VDC 2.0A 10.4W I'm building a circuit I want to power via USB and I calculated it would sink 500mA from ...
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1answer
155 views

Can the USB port's metal enclosure be grounded?

As shown in the image below, the USB port's metal enclosure is touching the copper clad of the PCB (which is a ground plane). Can Bad Things Happen™ if the port's enclosure is grounded? I beep-...
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2answers
202 views

Why is buffer received over USB is not aligned on transmitted buffer length?

I stream some data from STM32H7 USB (VCP) -> to PC, and after stream is finished I just send "end\0". And on PC side I just look at the start of received data block and if there is "end\0", I just ...
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1answer
125 views

USB over RJ45 to USB C [closed]

I am working on an Arcade Stick/Fight Stick enclosure. Internally, the PCB (Brook UFB) runs USB over a standard Ethernet cable, to a Neutrik RJ45 passthrough. I typically then create an RJ45 to USB A ...
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1answer
2k views

USB connector pinout

I am planning to use this USB connector but I am having trouble finding the pin-out: https://www.digikey.in/product-detail/en/USB-A1SSW6/ED2991-ND/2677752 I checked 3-4 different manufacturers and ...
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3answers
330 views

Confusion over the power wires of USB (GND and +5v)

I'm converting a battery powered device to be powered off a USB connection. I think I have everything figured out except one thing. I understand there is a GND wire inside the USB cable for power, ...
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2answers
116 views

Two 5V2A powerbanks draw different current under same conditions?

I have 2 different powerbanks, both have 10000 mAh and both are rated for 5V 2A power input. I have noticed that they draw a different amount of current despite using the exact same charger (5V 3A), ...
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2answers
120 views

What happens when devices request different voltages from a USB hub? [duplicate]

I'd like to charge two devices with one USB charger, one requests 5V, the other 9V. I plug an USB hub (potentially an old USB 2.0 one) in the (9V capable) charger and plug the two devices in the hub. ...
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2answers
452 views

Ferrite bead in cable or in device?

I am wondering, I made a MIDI circuit and was advised to use ferrite beads in my device for MIDI input/output. It is a similar to the following circuit (only the L1/L2 ferrite beads are important for ...
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2answers
305 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 ...
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3answers
104 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 ...
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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?
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1answer
115 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
62 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 ...
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1answer
62 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. ...
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1answer
175 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 ...
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1answer
73 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
45 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 ...
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1answer
103 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 ...
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1answer
52 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 ...
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1answer
312 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 ...
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3answers
124 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 ...
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1answer
63 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 ...
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2answers
185 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 ...
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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 ...
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2answers
128 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 ...