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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.

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How to determine IBM USB 6 pin header pinout?

I have two IBM Power 7 machines - Power720 and Power740 (8202-E4B and 8205-E6B) and both have an internal USB 6 pin header (labelled J3_TAPEUSB_SIGNAL). These are for connection to a single device (...
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1answer
53 views

Measuring USB power adapter quality using multimeter

I have heard horror stories about poor quality USB power adapter. I have a collection of no less than 20 USB power adapters, most are from cell phone manufacturers and some from small projects. I ...
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1answer
48 views

USB Power Only - Detect Device Plugged In

I have a project that I need to complete for work. We have been working on this project for a while, however I have come to a bit of a road block. I'll first lay out the important points. We have a ...
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0answers
65 views

Power switch - IN and OUT connected all the time

A while ago, I asked about detecting whether a power jack is connected or not, in order to select power source from USB or DC jack. You can see the question here: Power selection circuit for USB or ...
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1answer
32 views

How to deactivate Li-Ion battery charger

I have a USB device, which does have a Li-Ion internal battery in it. The device charges the battery when plugged into a socket. However, I don't want that battery to be used at all, I do prefer that ...
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1answer
40 views

Is less than 1A enough for TP4056 module to charge one battery?

I want to charge 3 separate 18650 cells with one charger. Each one of the batteries has their own TP4056 module. So in total there are 3 TP4056's. I know that TP4056 is rated at 1 amp input, though my ...
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1answer
70 views

How to test if the USB data lines are being passed to the port?

We have an white label manufactured Android tablet that snaps into a dock made by the same vendor. A USB port on the tablet is replicated to the dock, which has a Type A port that we plug an RFID ...
2
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1answer
58 views

Low-Power over USB

I have a small custom 5V 2mA device which is powered over USB. To be specific, it will be powered over USB by connecting it to an Android smartphone or an iPhone. There is no data transfer. I ...
2
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1answer
87 views

Which pin of USB-C to use for analog signal?

I am working on a project which connects a microcontroller to an IR sensor device and decided to use a male-male USB C since I need 5 lines (V,GND,SCL,SDA,ADC). Which pin should I use for my single-...
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2answers
78 views

Does MicroUSB B have 5 seperate lines?

I am working on a project that requires a 5 pin connector but it seems like the USB cable is causing some issues. I am using a microUSB B male-male cord to transfer some power and data. Through ...
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1answer
39 views

What ICs are required to transmit DisplayPort over USB-C alt mode?

If I have a DisplayPort 1.2 source and I wish to transmit the displayport video signal down a USB-C cable to a monitor, do I need a USB C port controller like an EZ-PD CCG6 or could I just connect the ...
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2answers
62 views

How does USB port on a power strip detect the optimal current output?

I am looking to buy a power strip with USB ports and came across this one online. The description says "Top-notch USB smart charging technology which can detect and deliver optimal current output up ...
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3answers
66 views

USB current draw and CE marking

We have developed a docking station product which charges multiple devices simultaneously, and currently ships with a 5V, 3A barrel jack adaptor. We are looking to move this over to USB power, and ...
1
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1answer
31 views

ATmega328P running on 3.3V using a CH340G as serial to USB interface

I'm trying to use a CH340G chip with an ATmega328P that is running on 3.3V to have a simple serial to USB interface. The available datasheets for this chip seem to be very minimal so I've tried ...
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0answers
22 views

Transferring uint32_t using USB_OTG_FS in stm32f4 discovery board

i want to send an uit32_t adcbuffer[1] over USB at full speed and CDC library but as you can see ...
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1answer
66 views

Fpga communicate to pc through usb

I'm currently working on my thesis project on making a secure pendrive. For that I have to design an USB protocol implementation on an FPGA. But I don't know how to physically connect that USB core ...
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1answer
44 views

How to transfer data which is acquired by ADC & DMA using USB_OTG_FS in stm32f407 discovery board

i acquire a 12 bit ADC at 10kHz sampling rate (which is equal to 15 kByte/s) using DMA2/stream0 in circular mode and put them into an unit16_t adcbuufer[1] now i ...
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1answer
46 views

precision, isolated current monitor with USB interface [closed]

For my work in developing very low-power microcontroller-based systems, I often need a way to dynamically monitor the current of the system under development. My ideal system would be a simple USB-...
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2answers
46 views

USB EC vs PIC MCU [closed]

I'm trying to make a peripheral with an embedded USB hub, which will include USB-C 3.1. As I've been researching USB I've found that Microchip has a whole slew of embedded controllers dedicated to USB,...
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2answers
69 views

Analog Potentiometer Output to USB Serial [on hold]

I‘m working on a project which has several switches and potentiometers that will be used to control parameters in software via (e.g.) MIDI and would like to know how to get the pots set up without ...
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1answer
59 views

USB C connector design and resistor placement for USB 2.0 data cable

I have a follow-up question to this one. I have a type C connector with 8 pins. No spec, type C female counterpart reveals G, Vcc, A2, A3, A6, A7. Remaining two pins do not respond to anything. G-Vcc ...
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2answers
49 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
47 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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0answers
109 views

STM32F103C8T6 fake?

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
54 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 ...
2
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1answer
49 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
71 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
27 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
117 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
81 views

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

Looking for a 5V portable power source without switching or conversion noise.
12
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1answer
454 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
57 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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0answers
20 views

How does “Always On USB” work [migrated]

I have a Lenovo laptop. There is a feature called "Always On USB" which allows devices connected to the laptop via USB to be powered over USB even when the Operating system (Windows 10 in my case) ...
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1answer
92 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
28 views

Connect old USB webcam to USB Host Shield 2.0 Arduino Uno / Mega [migrated]

Does anybody know how to interface an old USB webcam with the USB Host Shield 2.0 connected to an Arduino (Uno or Mega 2560 or other models - excluding Yun). I've got the USB Host Shield set up ...
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0answers
28 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
69 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
30 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
49 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
30 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
65 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
96 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
53 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
81 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
166 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
72 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
128 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
61 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
63 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 ...