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Is it possible to connect Pic directly to usb

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Full Member level 6
Nov 18, 2001
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serial interface engine avr


I would like to know if it is possible to connect pic mcu (for example 16f628) directly to usb port? A guy connected atmel mcu directly to usb.May be it can be possible to do that with most common mcu. Look at this : :roll:


connect pic

Well, if you read the page you have linked to, then you will find the answer for your question.

Don't bother with the link. It's just some
porn site.

Pfff...Just change xxx to www!

Anything is possible, but is it worth the effort? USB is a high speed differential analogue interface, it is possible to get a Serial interface engine IC to convert this to digital, but then you have the protocol to sort out, bit stuffing, clock synchronization, packet recovery, handshaking and all that. It is a lot less headache to use a pic chip with a USB port on it such as the 16C765. Only supports low speed usb though. Or use a chip like the philips PDIUSBD11/12 as the usb interface.
Microchip have been threatening to bring out a full speed version for some time, still a future product though. If it was easy, they would have it on the market by now.

It is not a porn site. You have to replace xxx with www in the link. I don't understand why you don't make the correct link, there is nothing illigal in that.

Here is a part of the article:

Firstly I choose PIC16F84-20, with which I have experiences. To ensure synchronizing with USB clock and speed increasing was used microcontroller clock 24MHz = 6MIPS (PIC was slightly overclocked). For one bit from USB processing were 4 instructions (4=6MIPS/1.5Mbit for LowSpeed USB). I reject this solution (after some time) - PIC is too slow (and in addition the no so good instruction set ...) .

As you can read the PIC i too slow to make it work with a software-based USB-interface, so you have to use an Atmel.
Otherwise you have to use one of the PICs with built-in hardware USB-interface - just like you can read in the article if you bother.

ccs pic c has solution for usbn9xxx and onchip usb can try...
you can find this compiler from MCU..programs...ccs



I believe some of the newer PIC chips, I think the 18F series, has a built in USB port.

That's correct but he wanted to connect a PIC without hardware USB. Just a software USB soloution for a PIC hardware USB. But the PIC is not fast enough for this you have to use an AVR or a PIC with harware USB interface.


And if I would like to use an AVR or SX, where would i find specs to program a USB interface? is there one implemented?


Here's the link for the english version of AVR USB interface:

**broken link removed**

Not so good as the link posted above, but at least give it a try:

The following design does not meet all USB requirements
and provides just an example of simple interface to USB using Scenix MCU and widely
available components:
bus driver 74LCX125
Resonator - 50 MHz (Murata)

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