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

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3
votes
1answer
44 views

Why does usb have start of frame packets?

I'm developing some high-speed 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 send a ...
0
votes
0answers
35 views

USB Full-Speed driver's effect on transfer speed

I am experiencing problems with USB communications which seems driver related. My setup involves an embedded device set up as a virtual com port (CDC/ACM) with which I communicate over USB. The ...
-3
votes
0answers
21 views

USBH and GUI thread not running (from Keil examples) [on hold]

I am currently working on http://www.keil.com/appnotes/docs/apnt_268.asp example and stuck at stage 3 and 4. These stages set the RTOS thread stack size to 1000bytes and total stack size to 4096 and ...
-4
votes
1answer
74 views

Trying to get this damn keyboard to work [on hold]

I acquired a keyboard from an electronics recycler. Its a one off for a broadcasting company, and it did not come with a cable. Its 10pin rj45 to USB, and I know there is no converter in the cable. ...
1
vote
0answers
15 views

ESP8266 not responding with CP2102

I connected my esp8266 with USB to TTL CP2102 as follows: ...
3
votes
1answer
36 views

Can a USB device attempt to be bus-powered and then fall-back to self-powered?

The device has a battery, but it would be nice to be bus-powered when available. A computer will typically supply 500 mA, for instance, while a smartphone in OTG mode is only required to supply 8 mA. ...
1
vote
0answers
53 views

Is it possible to write data directly from a mobile to a PC through the mobile's SD card slot? [migrated]

I have to questions: -Is it possible to write data directly from GoPro to a Raspberry Pi through the GoPro's SD card slot? -How does Micro SD card function? I would like to use my GoPro (hero 1) as a ...
-2
votes
1answer
63 views

Is there supposed to be a voltage differential between V- and Earth Ground on my Power Supply? [closed]

I'm debugging something in my machine that's causing it to blow my communication chips (AtMEGA16U2 for USB connection) when I noticed a voltage differential of 0.3VDC-0.9VDC between V- and GND on the ...
-1
votes
3answers
41 views

Can I power this device with a USB port? [closed]

I have an audio looping device known as the TC Electronic; Ditto Looper. It has its own dedicated AC/DC power adapter but I was wondering if I could possibly build a cable capable of powering it with ...
-1
votes
1answer
53 views

Building a USB Charging Circuit Using 120VAC

first time here. I've been working on developing a 3-port USB charging circuit coming out of a 120VAC wall outlet. Here is a basic schematic of what I'm following. I've been having some trouble ...
0
votes
1answer
25 views

Powering USB hub using fast charger

I'm working on a project where there will be 3 USB devices and a Qi transmitter that are hooked to a USB hub board. I just need USB High-Speed, not 3.0+. The 3 USB devices would consume total of ~1A. ...
2
votes
1answer
86 views

STM32 “USB Device” vs. “USB OTG HS” - what is the difference?

I recently downloaded the stm32 app for MCU search and found out that for example STM32F429 has "NO" in "USB Device" peripheral, while it says "YES" in "USB OTG FS" and "USB OTG HS". Which is quite ...
0
votes
3answers
39 views

Audio Signal Noise: Understanding & Troubleshooting

Today, I'm wearing a pair of active headphones for a change.. ( Running on 2x AAA batteries ). I've hooked them up to a synth and noticed this really annoying monotone buzz / hum in the background. ...
0
votes
1answer
30 views

Problem in circuit that charges tablet/cell phone via Micro-USB port

I am trying to design a circuit that can charge tablet/cell phone via micro-usb port. Attached is the circuit I put together. The basic idea is, take 6 ~ 12V DC from an AC-adapter, then step the ...
0
votes
0answers
42 views

tingly feeling when moving finger [duplicate]

while charging my Ipod or other USB based devices from a wall wart, i get a weird feeling, only when i move my finger against the metal surface. for example, the metal back panel of the ipod. Am sure ...
0
votes
1answer
39 views

Control USB powered light with PWM, would it work?

A few weeks ago, I asked about controlling a DC powered LED lamp using PWM here, I was told that if I can get a LED lamp that uses an external DC adapter to power up, I can use a MOSFET and control it ...
0
votes
0answers
32 views

Reading text from a USB drive connected to an ATMega1284

I am embarking on a project to create a very crude "crypto module" to learn some basics about how a hardware encryption module might be implemented. I understand right off the bat that on the whole ...
-1
votes
1answer
60 views

How to build a DC-DC USB step up adjustable converter 2A? [closed]

I'm trying to find a reliable electronic diagram for a USB adjustable converter (5V~>6V~>9v~>12V). So what I'm tying to do is to use a powerbank (it doesn't have the off function is the draw is low) ...
0
votes
1answer
35 views

Does it matter what the input voltage is to a DC/DC step-up converter?

I have a converter that outputs 5v and 1 amp. The input voltage can be 2.5-6 volts. Does it matter as long as it is in the range? Also, will the current draw from the batteries differ if I change the ...
-4
votes
0answers
37 views

Help to build Mini PCI-E add-on card for Raspberry Pi 2 [migrated]

Is it possible to build an add-on card that has mini PCI-E slot, SIM slot and LED and that can be attached to Raspberry Pi 2 GPIO header? It would save me one USB port and it would be more neater ...
0
votes
1answer
54 views

What are USB Connectors made of?

What type of metal are the tips of USB connectors/plugs typically made from? Aluminium? I've noticed they will often, quite-easily, oxidise/rust/corrode.
0
votes
1answer
62 views

Build own custom USB 'regulator' adapter board to solve Desktop boot hangs with KVM

My Desktop PC hangs in the BIOS boot phase when my KVM is attached. If I unplug the USB connecting the PC to the KVM, the PC boots without hanging. If the USB of the PC is connected directly to the ...
0
votes
0answers
33 views

System not working as expected - resistance measurement

I found a problem while measuring the resistance from PCB1. When both the FETs are enabled on System 1,the resistance is measured. PCB1 is powered from USB port 1 and system 1 is powered from ac-dc ...
1
vote
1answer
61 views

Switching USB connections between two devices?

I currently have plans to convert a keyboard to bluetooth using a bluefruit module, but I would also like to have a switch to make it wired if I ever want to plug it in. The bluefruit module is being ...
0
votes
1answer
78 views

Switching between two power supplies with a P channel Mosfet, Is VGS or VDS a problem?

So I am using the following circuit to switch between VIN 0-30v and USBVIN 5v. I thought I found the ideal solution until I realised the FET in the schematic only has a max VGS of 8V. But I don't ...
0
votes
0answers
32 views

Device descriptor stall on windows, works on linux microchip mla

I'm designing a USB device with Microchip's MLA v2015-08-10 on a PIC24FJ128GB202. The device works as expected on my Fedora 23 Linux system. It enumerates and is recognized as a HID device. On ...
3
votes
1answer
43 views

Is UL approval at all possible for low voltage USB and network LAN Cat6 patch cables

I am from a European distributor. Some of our customers, who export to the US are asking for UL approved Cat6 and USB patch cables. Is it even possible to UL approve these low volatage cables? i.e is ...
0
votes
1answer
65 views

How to connect micro-USB to voltage regulator for MSP430 microcontroller?

I am going to use a micro-USB to power my MSP430 microcontroller. That means I only need the 5v and the GROUND pin. However, after discussing that the other pins should be untouched.. my friend said ...
0
votes
1answer
32 views

Programming USB OTG PIC32 through USB in MPLAB

I have a PIC32 that has USB OTG. How would I program it through a USB cable in MPLAB? Does it work out of the box of does it need additional software.
0
votes
1answer
35 views

STM32F439 CDC driver, is using UART required?

So, most of the examples use USB CDC driver and they bridge UART. I'm not embedded guy and learning the stuff one by one. So, I understand UART... But I'm a bit confused how this bridging works. Is ...
1
vote
1answer
43 views

USB Connector Current Rating for Charging

I have heard it mentioned that the current rating for a USB charger is dependent on the current rating of the USB port itself; ie a Type A connector has to be rated for 2A on a charger that says it ...
0
votes
3answers
129 views

Can I charge a 12v toy with USB? [closed]

I have this small palm sized toy drone. It uses a 'charger' which houses 8 AA alkaline batteries. The charger plugs into the drone and the charger is activated by a toggle switch. I want to replace ...
0
votes
2answers
88 views

How to connect multiple micro-controllers' USB ports on the same PCB?

I'm designing a PCB with 3 Atmel ATmega16U4-AU micro-controllers on it. I will be programming them through SPI. Therefore, I will not be using D+ and D- ports on the USB interface. Then how do I ...
7
votes
2answers
107 views

5V tolerance on VBUS sensing input

I am designing a device around the STM32L476. My device is primarily battery-powered, but has a USB port that, when plugged, I want to use as an alternative power source (through a 3.3V regulator) to ...
0
votes
2answers
96 views

Confused about how microcontroller board and computer communicate

i recently got myself FRDM K64F board and got myself occupied with the following questions : Does the compiled hex code i send to my board has to go to the uart chip prior going into ...
0
votes
1answer
54 views

How to “frankenstine” wires?

How do I make a different usb wire type out of two different usb wires? For example, say I have two standard usb-to-micro-usb wires and I want to make one usb-to-usb and then one ...
-2
votes
1answer
53 views

What is the difference between “FS Device”, “FS Device/Host/OTG”, and “HS Device/Host/OTG”?

I'm going to buy a PIC32 which has inbuilt USB support. What is the difference between "FS Device", "FS Device/Host/OTG", and "HS Device/Host/OTG"? Am I right in thinking that the "OTG" aka "on the ...
0
votes
1answer
27 views

5v usb cable to power a 2AA Kitchen Scale [closed]

This is my first question and I'm a total beginner at this, so, please be kind :D I have a kitchen scale that eats up 2AA batteries every 2-3 days, so I thought to power it via a USB wall charger ...
0
votes
2answers
53 views

Adding an on/off switch to an USB charger [closed]

I was wondering if it is possible to wire an on/off switch into the cable of a wall-wart USB power charger as easily as it is to wire an on/off switch into a regular power cable? Or are there ...
0
votes
0answers
38 views

How to boost a small solar panel by a few volts?

I have a 4v solar panel, and I have load that takes 5v. So, how can I just increase the solar panel by 1 volt? Thanks.
0
votes
3answers
51 views

Simple USB powered PIR sensor with LED attached to it (no arduino)

I'm new here and I'm re-new in electronic hence why I'm seeking for some help. Last time I touched a breadboard with a transistor was 10 years ago. So, here's my problem and the problem to the ...
0
votes
1answer
45 views

Is there a usb controller IC which give MCU USB capability?

It is disappointed that the MCU I want to use in my project does not have USB controller nor USB PHY capability. Can I simply add one standalone USB controller IC? I see device like FT2322h can ...
0
votes
2answers
44 views

Can I use a point-of-load converter for providing USB power?

I'm designing a power supply that I would like to have a USB power output for charging/powering USB devices. In an effort to reduce risk and design time, I'm looking at mounting a DC/DC converter on ...
0
votes
1answer
40 views

Raspberry Pi 2 to arduino RF Serial link with USB to Serial TTL Converter

This is my first question here. I want to have a communication channel which will use a 433 MHz RF TX-RX pair. I want to use a Raspberry Pi 2 as a transmitter and an Arduino Mega as a receiver. Is it ...
-1
votes
0answers
67 views

Feasibility of HID gyroscope

I'd like to add a gyroscope to my phone because, like many other from china, it doesn't have a gyroscope. I'd mainly like to use it for VR (with cardboard). How feasible do you think it is to create ...
0
votes
1answer
56 views

Regulating voltage so USB works with module

I recently purchased this GSM/GPS module. I would like to power this module via a USB cable but can see that it has varying input voltages. So bearing in mind that USB is 5V and that I'm an ...
1
vote
1answer
69 views

USB 2.0 layout on 2-layer board

I have laid out this board that includes (among other lower speed connections) a 1 upstream and 2 downstream ports on a 0.5mm FR4. The USB differential traces are 0.6mm wide with 0.15mm spacing ...
2
votes
1answer
90 views

rx_polarity inversion in USB3.x

As per USB3.x specification there is provision of rx_polarity_inversion can any one exactly says, what is the reason behind it? Edit: Normally connection of ...
0
votes
0answers
22 views

AM3358 Usb type C support?

Does the AM3358BZCZ100 have support for USB type C? or is USB type C just like any other USB interface, I am currently looking through the data sheet so probably will find it there.
3
votes
2answers
85 views

Waterproofing USB port

Recently Samsung came out with the new Galaxy and Edge phones which are advertised as IP68 rated.The mircro USB ports on these phones are completely exposed, yet are still IP68 rated. My question is, ...