I am working on a project which requires transfer of signals from external world to computer.
I have a source which generates analog signals, and this signal needs to be transmitted on the PC, via USB.
Here is my question:
What is the interfacing?
The analog signal which I get from the source, do I have to convert it into digital using microcontroller and then transmit via USB, or we can transmit the analog signal as it is through USB?
Also I tried cutting the USB wire and found 4 wires inside: V+, V-, Data+, Data-.
What is the significance of Data+ and Data-?
Data+ and Data- are wires of differential pair, which is used to transfer digital signal.
You cannot use them to transfer analog signal.
The simplest solution is any Arduino board, with AVR microcontroller and UART-to-USB converter (UART is much simple then USB). But actual solution depends on performance you need.
Related
I'm trying to configure/write VHDL code that would let me output or input data from the USB port on a Basys3 FPGA board. Problem is I have yet to found any threads or questions that talk about this topic.
The nearest thing to an answer I've found is this:
Provide input data to FPGA using USB
and it does not contain what I'm looking for.
Any clues anyone¿?
The Basys3 board has a usb-uart bridge chip as described in the reference manual. This will appear to a PC (or any device with a usb host and the appropriate usb-serial drivers) as a virtual com port. Sending data to and from a PC com port is quite easy.
You will need a uart implementation on the FPGA. There are lots of example designs on the web. One way is to implement a soft core microblaze processor with a uart peripheral in the FPGA. This example looks like it includes foundation for the functionality you desire.
The simplest implementation from the PC side is using a terminal program such as putty, Tera Term or realterm. Most languages include com(serial) port libraries or bindings. This type of interface tops out at a raw bandwidth of around 3-12Mbits per second depending on the drivers and implementation.
Read the manual for the Basys 3 board. It will explain how you can interface with USB devices plugged into the USB port. Be warned, however, that your options are pretty limited.
Short version: if you plug in a USB mouse or keyboard, they will be exposed to your design as an emulated PS/2 device. USB storage devices can be used to configure the FPGA. Other devices are not supported.
I have an Arduino Pro Mini and a USB cable with just wires from one side. Is it possible to connect these wires directly with Arduino? I mean, +Data to Rx, -Data to Tx, +5v to one of the numbered pins and ground to GND.
No, in fact you could damage your Arduino doing this.
The RX and TX pins are for Serial (which run at higher voltages than 5volts)
Your best option would be to buy a USB to Serial convetor and then use a MAX232 chip (it is a chip that converts TTL logic (5volts) to RS232 (3 to -25 volts).
Or you could try using the v-usb library. Google v-usb online.
Hope this helps.
Yes, but not as you think, there is a raw voltage and regulated voltage but why run the risk of wiring incorrectly.
The best is use USB device between FTDI.
Here is a simple pin connection to make programming easier in photos. (quality of photos may not be best but you get the idea from them) I don't show how I add the blue to the pins but that is shrink tubing heated.
This makes easier programming of your Arduino this can be attached to a programmer quickly and effectively.
You can get this from Sparkfun for very cheap FTDI
So I know that for a USB port type A there is 2 ouputs/inputs. I'm working on a simple electronic circuit and I would like to ouput datas on to my computer so a program could work with it. How (without it getting too complicated on the circuit side) can I just choose the output of the USB port and read the input just on the on/off level?
Thanks
What you want is the www.Nusbio.net device.
it is an USB device that give any .NET programming languages access to 8 gpios and also SPI and I2c bus.
USB is more complicated than what you are describing. It sounds like what you really want is a serial port, where you can use the TX and RX lines as your output and input to the PC, or manually control the modem control or GPIO pins. You can still do this with USB via a USB to UART Bridge device.
If you are simply looking to toggle an I/O pin, some of these devices also have general purpose I/O pins for this type of thing. You can set it to low/high from the PC if it is set to be an output and read the I/O value if it is an input.
You can talk to it as a serial device from your computer using normal serial communications such as POSIX method for Linux or OSX or the Commuincations API for Windows. In this case you can also set the flow control to manual and use the RTS/CTS pins as GPIOs.
You cannot directly control the USB inputs and outputs like you want to do. However, there are various solutions that involve connecting a USB device to your computer and sending commands to it that use its inputs and outputs. One such solution is called Firmata.
I am working on Xilinx Spartan 3E platform, using this development board:
http://www.xilinx.com/products/boards-and-kits/HW-SPAR3E-SK-US-G.htm
My program operates on certain data and then provides output. I wish to transfer the input signals externally. The input data is a stream of 8-bit signals.
So, how do I send the input signals from my laptop to the FPGA via USB? Does Xilinx support this or is there standard software to do this?
Thanks.
It sounds like you are describing a uart more than a native USB interface. You can get a USB to logic level serial adapter that will let you easily transfer data to and from a Pc at up to 921.6k baud. A uart/serial port is easy to implement in the Fpga and PCs are easy to use with serial ports.
Here is the cable:
http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm
If you have a development card it is very possible this type of interface is present.
On the software side you can use your programming language of choice as if it was interfacing with a seal port or use a terminal program like hyper terminal or Download teraterm http://ttssh2.sourceforge.jp/
Updated response:
100Hz is not a hard interface to make. At that rate you should use the serial interface if at all possible. The board you referenced has 2 full RS-232 connections. At that point you only need a way to connect that to your computer. If you have a PC with RS-232 connectors you only need a cable if you have a newer computer without you need a RS-232 to USB translator cable (like this one: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=768-1014-ND or google rs232 usb). This will give you a virtual com port on the pc to interface with the previously mentioned terminal programs or your custom software.
Update 2:
on the resource tab of the development board page you linked to there are several UART based fpga designs that you should be able to use as a starting point.
i.e. the "PicoBlaze Processor SPI Flash Programmer".
That board doesn't provide easy access to the USB interface from the FPGA as far as I can tell. It's just for configuration and debug.
Some of the newer boards and tools do allow something called hardware-in-the-loop testing where the simulator can upload data to the FPGA, wait it to calculate the results and then pull the data back. This is relatively common when using Xilinx's System Generator product as the simulations can be really long.
But I think with that board you'd be better off using the on board RS232 port to get data to and from the board. You will have to build the infrastructure to do it yourself though.
This may also give you some ideas:
http://www.1pin-interface.com/
I am planning on doing a small arduino project and would like to know if what I'm thinking would work with a regular arduino board. I'm thinking of buying an Arduino Uno for my project, along with an IR LED and an IR sensor. So here's what I want to go with this:
I want to point the LED towards the sensor, so that the sensor is always detecting light. Then', I'll start "cutting" that light (say, with with my hand) several times. I want the arduino program to time the intervals between the times the light is "cut" and send these times to my computer via USB, so I can process this data.
I've seen many people talk about serial communication between an arduino board and a computer, but I'm not sure how that works. Will it use the same usb connector I use to upload programs to the board, or do I have to buy anything else?
EDIT: tl;dr: I guess my question, in the end, is twofold:
1) Am I able to "talk" to my computer using the built-in USB connector on the board, or is that used solely for uploading programs and I need to buy another one? and
2) Is this project feasible with an Arduino Uno board?
Thanks for the help!
Yes, your project is very feasible.
You use the built in USB connector to both program the device and communicate with it. Check out some examples on the Serial Reference Page
For reading the sensor, you'll want to use either a digital or analog input. For a digital input, you'll likely have to external components to control the light threshold, but it will provide a simple yes or no if something is in front of it. With an analog input, you can use a threshold in code to determine when your hand passes.
Timing can either be done on device with the Millis() function or on the connected computer.