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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4answers
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Low cost FTDI cables?

I'm looking for USB to serial FTDI cables. However, the cheapest I can find is $20 US each, which is way too expensive, given my price target for the entire product is $70. I'm hoping they can be ...
4
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1answer
2k views

Using a P-channel mosfet instead of a PNP

With the LPC1343 microcontroller (Cortex M3), there is a USB_CONNECT line which goes low when the micro is ready to connect to the computer via USB. This "soft connect" feature is implemented on the ...
5
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4answers
9k views

USB without Vcc

I want to remove the Vcc pin from a USB cable and connect my computer to a device. My goal is to allow the device to communicate with the computer while not charging the device. Does some section of ...
4
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4answers
2k views

Small “FTDI”-like chip

I am looking for a small USB to RS232 (or TTL serial) converter. FTDI was the first stop, but the smallest IC they have is in SSOP28 or QFN32. I'm looking to go even smaller. I don't need high speed - ...
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5answers
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Computer to Arduino Interface Options

I need to send 800 bytes of data from a computer to an arduino board every 20ms (approximately). I began with the serial library which works nicely but it is too slow even at its highest rate (115200 ...
3
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2answers
3k views

How to assemble male USB A connector?

This one should be obvious, but I'd rather ask here then get some unexpected surprises. One of my friends fried a proprietary USB cable which has male USB A connector at one end and TRS connector at ...
3
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1answer
2k views

Which PIC MCU for an Audio player?

DESCRIPTION: It will play .wav and .mp3 files from a Micro SD Card. The memory card can be written through USB (its an in-board unit). It will have a LCD screen to show the contents and functions ...
3
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1answer
222 views

Only getting 33mA from a USB port

I attached split the end of a USB wire and attached a switch. When I press the switch, I measure 5V from the port, but am only measuring 33mA. Why am I getting only 33mA instead of 100mA?
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2answers
885 views

How to connect mbed to computer

How do I connect my mbed NXP LPC1768 to my computer. I have a USB cable and a breadboard. What else do I need? What connections do I need to make?
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9answers
144k views

How to get more than 100mA from a USB port

I heard that the current limit for a USB port is 100mA. However, I also heard that some devices can get up to 1.8A from a port. How do you get past the 100mA limit?
7
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1answer
44k views

How do I measure the voltage coming out of a USB port?

If I attach a USB cable to a USB port, and then strip the wire at the end, then how do I connect a multimeter to it to measure the voltage?
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3answers
5k views

Reading/Writing a usb flash drive

I wish to expose a usb flash drive and read it as raw binary data, particularly read each byte & simultaneously writing it to another flash drive. Given that I am working with an 8085 ...
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4answers
403 views

Male Apple Dock Connector => USB (power only)

I have an old external battery for Apple devices (has 30 pin Apple Dock Connector), and I want to repurpose it to be an external battery for all my USB devices. Anyway, I don't have much experience ...
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2answers
1k views

Problems with CDC Device Class

I'm using the Microchip 16-bit 28-pin starter board and the USB communication with the PC keeps breaking. There are two microprocessors on the board. The application processor communicates to the USB ...
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4answers
944 views

How can I connect the KT3170 (The DTMF reciever) to USB (4bit data)?

This will be my first try at USB intefacing ! May I know how to transfer the data from pins : 11-15 of KT3170 IC to USB ? Data sheet : http://www.datasheetcatalog.org/datasheet/SamsungElectronic/...
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2answers
1k views

Problems programming LPC1343 microcontroller in Ubuntu

When I copy a binary that works on a lpc1343 to the mounted usb-device representing the lpc1343 flash, the binary file is changed and does not work. Doing the same with the flash mounted via usb on ...
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1answer
948 views

Driving a stepper motor via USB and OSX

I am a total newbie for electronics and hardware programming, but I would really like to start practicing it. As a first achievement, I would like to find a simple step motor and drive it through a ...
14
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2answers
10k views

Serial newbie: why can't I just hook the wires up?

I'm trying to transmit from an ATtiny85 to a PC using Arduino-esque code over a USB-Serial converter without understanding very much of anything. I was shocked and appalled that it did not work. I ...
52
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12answers
59k views

How to connect USB Connector shield?

How should I route USB Connector shield on PCB? Should it be connected to GND plane right where USB is placed, or should the shield be isolated from GND, or should it be connected to ground through ...
7
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4answers
5k views

Reading data from a glucose meter

What would be the easiest way to read data from a USB glucose meter externally with a microcontroller. Not with the software that is provided. So how could I incercept the digital signals that are ...
3
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3answers
977 views

Logomatic v2 serial SD Datalogger issues

Hi i bought this data logger a few weeks ago, http://www.littlebirdelectronics.com/products/Logomatic-v2-Serial-SD-Datalogger.html I've been having some trouble with it. I read the data sheet and I'...
1
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1answer
339 views

how to enable and configure USB OTG for device mode on iMX31 Litekit?

I need to configure USB OTG on iMX31 for device mode. We need a raw channel between the host and target and usb seems to be the best suited. However I haven't been able to correctly configure the OTG ...
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7answers
13k views

Reverse engineering USB signals

Let's say there is a USB stick that is specifically for storing dates or days or some kind of arbitrary data. In order to access the data you must have the software. Is there any way to analyze the ...
8
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4answers
3k views

Advice for USB Sniffer

I am looking for a USB protocol analyzer and was wondering if anyone had any experience with one. So far, I am looking at an Internal Test Instruments and a Beagle USB 12. I only need to watch the ...
3
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4answers
2k views

Any ideas on how to implement a USB man in the middle circuit?

I'm looking for an easy way to get in between of a HID USB communication. Can it work by multiplexing a single usb port on an AVR? Thanks!
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3answers
2k views

Which AVR hardware for USB?

I wonder which hardware will be the best for playing with USB because its looks like a lot of projects only use atmega8 (or even attiny). But would it really be easier with an AT90USB which have the ...
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5answers
4k views

Anything special I need to know about RS232 & FT232R?

I'm trying to interface an XSens IMU with my computer, and I'm running into interesting difficulties. The IMU has an RS232 connector that just uses the pins VCC, GND, TX, RX, nothing else. The SDK ...
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4answers
1k views

Embedded system scripting [closed]

Does anyone have some cool ideas for a use of a scripting language on an embedded system? I'm thinking about the eLua project specifically. Basically, you need a micro with at least 64k of RAM, ...
5
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3answers
2k views

Transfer files from mass storage device to other machine via wifi

How can one build a device that presents itself as a mass storage device to a machine via usb, then whatever files are transfered to it, get sent to a remote location via wifi (can be ad hoc). ...
2
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1answer
475 views

What type of connector to use for pressure contact?

I'm designing a robot gripper that needs to pickup an electronic device (the size of half a laptop) and move it around. The problem is that when the device gets picked up, I need to establish a USB ...
8
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3answers
784 views

Passive listening to USB communication

Is it possible to passively listen on low speed USB communication? Suppose I connect a logic analyzer to D+ or D- line, will I see a valid data?
6
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2answers
934 views

Dual Role USB device on AVR

Is it possible to run both USB Host and USB Device controllers on top of an AVR (ATMega64)? Specifically, what I'm looking for is to receive data from a usb keyboard, and simultaneously sending ...
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4answers
16k views

Are Common Mode Choke Coils needed on USB?

I was looking over the schematic for the GumStix Palo 43 and noticed they used a common mode choke coil on the data lines coming in from USB. I understand how this design can help remove noise ...
3
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2answers
590 views

USB-to-UART bridge: protocol mapping?

I was wondering how does the protocol mapping work between the USB side and the UART side when dealing with the Microchip MCP2200? What sort of USB transfer type is used? bulk? isochronous? ...
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3answers
1k views

Problems with a RFID reader from SparkFun

I am hoping someone here can help me. I am having trouble with a RFID kit I bought from SparkFun. I purchased the USB RFID (SEN-08852) with the RFID Reader ID-12 (SEN-08419) and some RFID cards. ...
2
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5answers
779 views

USB Host device

I am looking at creating a USB host devices to talk to a standalone printer. Basically my devices would feed out commands to the USB chip and the pritner would print it without interaction of a PC. ...
32
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10answers
55k views

How to build a USB controller having knobs, sliders, and switches

How does one go about building an interface for a USB device that allows interfacing pots, linear/log tapers, and momentary/toggle switches to a computer? If someone could give me a high-level ...
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5answers
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USB scope probe - request for comments and ideas

Idea: Take one oscilloscope probe, and one USB cable. Cut the BNC connector off the oscilloscope probe, and the USB B connector off the USB jack and splice them together. Mount all the USB <--> ...
4
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2answers
1k views

AVR Stick Data Logger Usage

Has anyone used this data logger (or similar) with v-usb to collect data? http://www.sparkfun.com/commerce/product_info.php?products_id=9147 If so, what is the maximum times per second voltage data ...
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6answers
12k views

DIY USB Mass Storage Tutorial

I was just wondering if there was a tutorial anywhere on how to make your own USB Flash Drive and I don't mean take apart a USB and put the guts into something else, I mean put together the flash ...
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2answers
9k views

FTDI FT2232H (USB <-> UART) baud rates?

Anyone used one of the FT2232H chips from FTDI? Specifically, how do you figure out the permissible baud rates? The data sheet is kind of vague, and I have to pick something in the 1-3 MBaud range ...
13
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8answers
3k views

RnD on an EEG, Help required, what op-amp?

this is my first post, and I need some help/advice finding the right integrated circuits. I'll start by describing the project background a bit. I've received a fellowship to develop an open source ...
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5answers
2k views

RS232-to-USB Converter [closed]

Anyone have any recommendations on a good rs232-to-usb converter. There are a lot out there and from the looks of it some are hit or miss. Good driver support is a must.
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1answer
2k views

Issues migrating from ATmega88 to ATmega88P, with V-USB/AVR-USB?

I'm working on a V-USB (aka AVR-USB) -based circuit running at 5V (i.e. two 3.6V Zeners across D+ & D-) and at 12MHz. I tried an ATmega88P instead of the ATmega88 chips I normally use and I can't ...
5
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3answers
4k views

Apple Desktop Bus (ADB) to USB Adapter

I have an old Apple keyboard that I would like to use but it uses the ADB bus instead of the newer USB bus. Griffin used to produce a product called the iMate which was an ADB-to-USB converter but ...
35
votes
5answers
15k views

Switch between 5V power supplies?

I'm designing a board that can be powered either by USB or an ATX power supply. They can both be plugged in at the same time, independently. I'd like the ATX to provide 5V if its plugged in, but ...
29
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11answers
17k views

I'd like to learn how to make my own USB gadgets

I've been writing Linux character device drivers for other people's stuff for some time. I'd like to find a new hobby and the thought of making my own USB gizmos seems really neat. I would be ...