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RAMAROSAONA
Joined: 02 Jul 2010
Posts: 1
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| USB Keyboard |
 Posted: Fri Jul 02, 2010 11:09 am |
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I want to use a standard USB keyboard (PIH) on a 18F4550 project with LCD.
Is it possible to use the 18F4550 as a USB Host? How can I get the keycodes of the keyboard? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19967
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| Posted: Fri Jul 02, 2010 2:47 pm |
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No.
For a USB host, you need a PIC supporting USB 'OTG', or an external device like the Vinculum.
However....
Every USB keyboard I have seen so far, also works as a PS/2 keyboard. Basically, the USB/PS/2 adapters sold for these, _do not_ contain any adapter electronics. Instead they just alter the wiring directly from the keyboard to the PS/2 port, and the keyboard detects that it is connected to this, rather than to USB, and changes mode automatically.
The wiring is normally:
| Code: |
USB PS/2
1 4
2 1
3 5
4 3
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You also may need to have about 4K7R pull up resistors on pins 1, and 5 of the PS/2 connector.
PS/2 'host' code, is as common as anything for the PIC.
Best Wishes |
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newguy
Joined: 24 Jun 2004
Posts: 1924
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| Posted: Fri Jul 02, 2010 5:09 pm |
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Ttelmah,
Completely unrelated and off topic, but do you know if a USB mouse will also auto-switch to PS/2 mode as well? We're kicking around an idea at work and this will greatly simplify things if true. |
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jbmiller
Joined: 07 Oct 2006
Posts: 73
Location: Greensville,Ontario
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| Posted: Sat Jul 03, 2010 4:56 am |
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| Mice are the same (at least the ones I have) although I have to use them in PS-2 mode for interrupt mode. |
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