Quesions about the design of USB devices that connect to a USB host, such as a PC.
30
votes
7answers
20k 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?
21
votes
2answers
2k views
How do I make the Fairchild FSA9280/FSA9480/FSA880 BOOT pin trigger? (Samsung Galaxy S)
this is a bit of a long shot but I'm hoping someone has access to the full data sheet for one of the chips listed in the title, and can tell me what combination of VBUS_IN and resistors on ID_CON will ...
15
votes
6answers
857 views
USB B, mini B, or micro B for product design
I'm trying to decide which connector I should use for a USB peripheral I'm designing. Is there a guide for choosing one?
The device is a portable electronic scoreboard that's 16"x10"x1". It will be ...
9
votes
3answers
2k views
Reading a Micron 29F32G08QAA NAND Flash IC
It would be nice if this was a shopping question - but it is 99%+ likely to be an electronic construction question :-(.
I wish to find the quickest / easiest / cheapest way to read a 4GB NAND Flash ...
8
votes
2answers
2k views
How to limit inrush current?
I'm designing a device powered from USB. The device uses FTDI FT2232 chip for USB connection. Upon a command from a computer FT2232 chip should enable power via a MOSFET switch to rest of the circuit. ...
8
votes
0answers
388 views
How can V-USB screw up the built-in SPI of an ATmega328p?
I'm working on a V-USB project that shows up as a Keyboard using an ATmega328p. The USB part is working great (it's not my first V-USB project), but after I start the V-USB stack with ...
5
votes
2answers
765 views
RS232 vs USB CDC quality of service / should messages contain a checksum?
Does USB have a quality of service guarantee for data sent between my USB-CDC device and the USB host?
I know with traditional RS232 in a noisy situation (e.g. automotive diagnostic port) bad bits ...
5
votes
1answer
1k views
How to make usb 3G modem signal stronger with aluminum foil antenna?
I'm in an area with weak signal reception, but I'd like to make my 3G connection better at very low cost.
I heard using aluminum foil as reflecting surface and placing the modem in some way in front ...
5
votes
2answers
645 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 ...
5
votes
1answer
444 views
How do they calculate the output power?
I'm building a quadcopter using Cortex A8 and I would like to use this USB WIFI dongle.
According to the description this is 3000 mW. What does this mean? 3000 mW consumption? In the USB 2.0 the ...
5
votes
1answer
112 views
If I change the chipset of a USB product, should I change idProduct or bcdDevice?
The product looks outwardly the same, with the same model number, but the USB brains have been completely replaced, and the circuitry's been modified to fit them.
The operating system needs to see ...
4
votes
6answers
265 views
Need a device that can take single input and covert to a keyboard key press on USB
Let me explain what I'm doing currently.
We have made a finger heart rate monitor, each time your heart pulses a transistor is switched on via its base. The collector and emitter of the transistor ...
4
votes
5answers
752 views
Weird Toyota Prius and USB behavior
My brother in law bought a Prius recently. He's experiencing something strange with his iPod.
If he has his iPod plugged in via the USB cable to the Prius, everytime he starts up his car, it resets ...
4
votes
4answers
2k views
Is it possible to use a Microchip PIC32 as a USB host and device at the same time?
I'm designing a system and maybe (if I don't find better alternatives) I will need to use a PIC32 as a handler in between two USB devices and a host. My plan is to use the PIC32 to hide the devices, ...
4
votes
1answer
266 views
Does a self-powered USB device have to connect to VCC from the host port?
A self-powered USB peripheral provides its own power, so is it okay to connect just D+, D- and GND to the host port, or do you always have to connect +5V as well, then wait for the negotiation phase ...
4
votes
2answers
915 views
Arduino programming on Uno fails using USB download on Windows 2000
I have a number of W2K systems that we are trying to use to program the new Arduino Uno and Mega devices. These boards now come with a USB connection, an upgrade from the prior FTDI. I'm not able to ...
4
votes
0answers
208 views
Serial data transfer from Omega DP80 legacy hardware to computer
Can anyone provide me with some guidance on setting up a legacy serial connection on an Omega (brand) thermocouple display? I would like to use the serial data interface (Omega DP80-Ser) to reliably ...
3
votes
6answers
834 views
Is it possible to make a USB device that would alter mouse data on the fly?
I have a friend who is struggling to find mouse drivers/manufacturers that support various options for dyslexia. Inverting the X and Y axes are a simple feature that most programs and drivers are ...
3
votes
4answers
937 views
USB: what are the advantages (or disadvantages) or using HID over serial-over-USB?
Disclaimer: I'm a novice at electronics and even more so to working with USB, please bear with me if I misunderstand some of the essentials behind how USB works. Any correction welcome!
The scenario: ...
3
votes
1answer
274 views
Texas Instruments USB2ANY HPA665
I encountered device made by Texas Instruments with label USB2ANY HPA665. It has LED, mini USB and FloppyDiskDrive-like ports.
I can't find any data-sheet, manual or resources what for and how to use ...
3
votes
1answer
396 views
USB composite device driver
I am wondering if it possible to create a USB device (in following the device) composed from
a custom circuit (eg arduino) and ...
2
votes
3answers
1k views
Stability of USB +5V output
So i am designing a device that is supposed to connect to the PC via USB and draw power from the VBUS (+5v) of the USB.
I am wondering if I need to put a voltage regulator in between the +5v from ...
2
votes
3answers
541 views
How can I easily connect to my breadboard circuit using USB?
I'm looking to communicate with a circuit I have built on a breadboard. I would like to communicate using USB.
Can anyone suggest an item that I can use to accomplish this? Are their any other ...
2
votes
1answer
307 views
How can I communicate between micro-controller and PC without the use of RS232/USB Adapter?
I use an NXP micro-controller, P89V51RD2, and use a RS232 to USB converter to program it. I'd like to communicate with the computer to send data but without using the RS232 adapter and convert serial ...
2
votes
2answers
408 views
USB serial emulation: CDC or vendor-specific?
When designing a device that requires communication with a PC via a virtual serial port over USB:
When would one use usb-serial port emulation chips with vendor-specific drivers (e.g. FTDI) and
when ...
2
votes
3answers
543 views
Solutions for implementing a USB Mass Storage Device
I'm trying to figure out a convenient way with which a PC can configure an embedded system. The PC will have a custom app. written that can 'talk' to the embedded uC and configure the various settings ...
2
votes
1answer
223 views
USB inrush current
This is related to a few different questions (question 1, question 2).
From question 1, I have a device with rather high decoupling capacitance which exceeds the USB 2.0 ...
2
votes
1answer
491 views
iPad Doc connector: is it possible to using the camera connection kit while charging the ipad
I'm building a touch screen kiosk using an iPad and a USB BarCode Scanner (through the camera connection kit).
the problem:
The pinout here shows the USB pin that the scanner would connect to. ...
2
votes
1answer
98 views
Simple circuit to detect a boolean value on usb port
I want to automatically record all my calls from my analog telephone line.
I know how to set up to record directly from the phone's microphone but the problem is I don't know when to start the ...
2
votes
0answers
107 views
Send signal to USB with linux [closed]
I have a digital caliper/gauge: it works with FTDI interface and digimatic (or very similar) protocol. It is connected via usb port. I can connect it correctly, and I can read it with programs like ...
1
vote
2answers
104 views
USB device with a serial number and 3 LEDs
I'm looking for a way to build a USB key. I have a bit of experience with the Arduino, however for this project that seems to be a bit of overkill.
The key should contain a unique serial number ...
1
vote
2answers
213 views
Anyone know of a good/cheep usb dongle to pick up ULF (.3 - 3kHz) radio?
I've bought a pack with 3 temperature senders and 1 receiver. But I want more, and I also want datalogging.
Is there a USB dongle that let's me pick up on a given frequency, lets say '433.92 Hz' and ...
1
vote
3answers
330 views
Drawing 100mA / common ground for a bus-powered USB hub
I am trying to provide an external 5V power supply to a (previously) bus-powered USB hub.
My first attempt at this was to just connect the USB host's data pins to the hub's data pins, and the ...
1
vote
2answers
237 views
USB Hub project
I have a D-Link 7 port USB 2.0 hub model DUB-H7
The hub has a AC power supply that came with it, 5v 3amp output.
Problem, the hub will not supply 5v power to the 7 ports unless it is connected to a ...
1
vote
4answers
249 views
Tips when choosing relays
I need to control 3 devices, via three relays. I wish to use a 4-relay/usb controller to do this.
I currently use this device but I now need three relays:
http://www.barix.com/Barionet_100/511/
My ...
1
vote
2answers
461 views
What type of USB Protocol for Datalogger
I am attempting to create a USB datalogger and would like to first start with creating a program that transmits Hello World over USB not using some kind of CDC communication. I am trying to figure ...
1
vote
2answers
116 views
Can I make power consumption analysis much harder by temporarily disconnecting the power supply?
I am thinking about building a dongle that acts as a USB or PS/2 keyboard device and is capable of doing some cryptographic things for me, e.g. provide time-based authentication codes, store passwords ...
1
vote
2answers
301 views
High power LED's and a computer Power Supply?
Is it possible to dynamically power a multitude of approximately 1W LED lights via a computer/computer power supply. Ideally I would like to be able to control these LED's via a USB interface or ...
1
vote
1answer
2k views
FT232R eeprom problem .. how to make PC recognize it
it's my first time to use FT232R ..
when i connected it to the USB for the first time .. my Windows recognized it well, and its drivers were successfully installed ..
and even after programming it ...
1
vote
1answer
127 views
USB-device on SAM3-H256 - advice?
I want to build a device which should act as a USB keyboard. I've found a
SAM3-H256 board to be fairly easily available in my country. I want the device to be:
fully USB-powered (no additional power ...
1
vote
0answers
51 views
Interfacing NAND flash with USBMSD
I'm trying to read files from a NAND flash (K9LAG08U0M) that I took off an old MP3 player, so far I've been able to read the NAND contents successfully by interfacing it to my PC as a USBMSD (Mass ...
0
votes
3answers
2k views
Could a USB wifi dongle be used as an Arduino Wifi module?
I have seen many arduino compatible wifi modules that are rather expensive compared to some other types of modules. I am wondering what is the feasibility of using a consumer grade wifi usb dongle as ...
0
votes
1answer
427 views
Need Realtek's rtl8188cus (WiFi USB dongle) datasheet. Any advice?
I have to develop a driver for Realtek's rtl8188cus (WiFi USB dongle), but couldn't find any datasheet or any kind of how-to...
I contacted RealTek but they don't seem to respond.
Any advice ?
0
votes
1answer
83 views
Is it important to have common ground between you microcontoller and high-power devices on the same PCB?
I noticed that there are more N-channel mostfets than P-channel mosfets on the market.
Then I realised that probably in many applications, the high powered device runs on a higher voltage and ...
0
votes
2answers
1k views
Supply power to USB with external power supply
I have a device (pyro-electric array detector) that connects to the Pc vis a usb. The device itself has an additonal power supply as well.
Now a strange thing happens: If I connect the device to a ...
0
votes
1answer
695 views
USB barcode scanner and Arduino
I have a USB barcode scanner and I have difficulty getting the data out of it. What I did was to get one of these adapters, and followed this tutorial with no luck. When I connect the ports as shown, ...
0
votes
1answer
88 views
Help me interpret this part of the USB + Power Standard
It's the last two sentences of this section:
What does the last sentence mean exactly? And how do I apply it?
Basically I am building a USB + Power peripheral that will convert USB to RS-232 and ...
0
votes
1answer
38 views
bluetooth earphone with usb
I have a Sony bluetooth earphone. It has a usb terminal, which I thought it was only for the purpose of charging power. But when I connected it to a computer, it seems like it is detected as a usb ...
0
votes
0answers
13 views
Can USB 3.0 device initiate communication with USB 2.0 computer? [migrated]
I want to copy files from a computer with USB 2.0 support to an external drive with USB 3.0 support, but do not trust that the external drive is free of malware. Can a USB 3.0 device initiate ...
0
votes
2answers
74 views
Arduino Clone is not talking to my Mac
When I plugin my Osepp Uno (off-brand of Arduino Uno), the LED flickers a bunch, then the RX and TX lights do the same. But when I
ls /dev/ | grep -i usb
I get ...
