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Connect my circuit streight to USB port? Answered

Can I connect a circuit streight to the USB port?
There are USB driver circuits available in the market.
Previously I used to connect my circuits to LPT port or RS232 port.
Can I connect those circuits to USB port without any other driver circuits?


You can't connect "traditional" circuits straight to USB , anymore than you can fasten your monitor to an RS232 port.

All you need is the FTDI FT232 chip, or a board like this.

This instrument might be useful : www.delcom-eng.com/downloads/USBIODEV.pdf

Check this address : www.delcom-eng.com

Depending on what you want to do, you could also get a DIO circuit from national instruments.

"at least an LED" yes, there's 5V @ 100ma. Your binking is something else though.


Are you just trying to power it? What kind of circuit is it? How much current does it require? If you're just powering it then maybe. If it uses 5v and less than 500ma then it should work. Some USB ports may limit their power to 100ma but it still may be enough for your circuit.

I want to atleast blink a LED and control its ON/OFF from my application.

Your circuit must speak the USB protocol, or you must have a usb to serial adapter that speaks RS232 and creates a virtual com port on the computer for you to communicate with. There are some pic libraries that allow the uC to talk directly with a usb port.