Is it possible to connect Pic directly to usb

[Analyzer]

serial interface engine avr

Hi,

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:

http://xxx.cesko.host.sk/IgorPlugUSB/IgorPlug-USB%20(AVR)_eng.htm

Analyzer

 

[ME]

connect pic

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

 

[Nick C.]

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

 

[Analyzer]

Pfff...Just change xxx to www!

 

[btbass]

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.

 

[ME]

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.

 

[H_u_n_t_e_r]

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

Regards.

 

[rchadwick]

USB

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

 

[ME]

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.

 

[System.out]

.

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?

Thanks

 

[ME]

Here's the link for the english version of AVR USB interface:
http://cryo.pslib.cz/~cesko/IgorPlugUSB/IgorPlug-USB%20(AVR)_eng.htm

**broken link removed**

 

[silvio]

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)

http://www.sxlist.com/techref/ubicom/lib/io/dev/keys/usbdemo-mh.htm