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Analyzer
Joined: 18 Nov 2001
Posts: 414
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 18 Feb 2003 20:53 serial interface engine avr |
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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 : 
http://xxx.cesko.host.sk/IgorPlugUSB/IgorPlug-USB%20(AVR)_eng.htm
Analyzer
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ME
Joined: 14 Mar 2002
Posts: 1523
Helped: 13
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18 Feb 2003 21:35 connect pic |
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| Well, if you read the page you have linked to, then you will find the answer for your question.
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Nick C.
Joined: 20 Dec 2002
Posts: 184
Helped: 4
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| 18 Feb 2003 22:03 |
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Don't bother with the link. It's just some
spam site.
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Analyzer
Joined: 18 Nov 2001
Posts: 414
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| 18 Feb 2003 23:26 |
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| Pfff...Just change xxx to www!
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btbass
Joined: 20 Jul 2001
Posts: 1187
Helped: 113
Location: Oberon
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| 18 Feb 2003 23:29 |
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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.
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ME
Joined: 14 Mar 2002
Posts: 1523
Helped: 13
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| 18 Feb 2003 23:58 |
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It is not a spam 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.
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H_u_n_t_e_r
Joined: 24 Nov 2001
Posts: 207
Helped: 4
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| 02 Mar 2003 12:20 |
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ccs pic c has solution for usbn9xxx and onchip usb pics..you can try...
you can find this compiler from MCU..programs...ccs
Regards.
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Google
AdSense
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02 Mar 2003 12:20 Ads |
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rchadwick
Joined: 22 Feb 2002
Posts: 25
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07 Mar 2003 7:02 USB |
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| I believe some of the newer PIC chips, I think the 18F series, has a built in USB port.
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ME
Joined: 14 Mar 2002
Posts: 1523
Helped: 13
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| 07 Mar 2003 19:16 |
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| 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.
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System.out
Joined: 11 Jan 2003
Posts: 74
Helped: 1
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07 Mar 2003 22:07 . |
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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
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ME
Joined: 14 Mar 2002
Posts: 1523
Helped: 13
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| 08 Mar 2003 13:55 |
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Here's the link for the english version of AVR USB interface:
http://cryo.pslib.cz/~cesko/IgorPlugUSB/IgorPlug-USB%20(AVR)_eng.htm
http://cryo.pslib.cz/~cesko/hardware.php
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silvio
Joined: 31 Dec 2001
Posts: 801
Helped: 90
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| 08 Mar 2003 14:36 |
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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
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