Hello, PIClist.

I am trying to make a USB-connected PIC18F2553 send some kind of event=20
every 30 seconds or so, to keep the screensaver on my Windows 7 PC from=20
activating while idle.

I figured the most innocuous events to send would be "volume up"=20
followed by "volume down" keypresses.  I presume these key events will=20
reset the screensaver timeout, and don't see them affecting much else=20
that might be in the foreground.  I want to leave the device plugged in=20
at all times, and mouse movements or virtually any other keypress might=20
be misinterpreted depending on what I'm working on.

I am using JALv2 and have the following code running. However the 0x80=20
and 0x81 scancodes for Volume Up/Down do not seem to be recognized by=20
Windows.  I have changed them to "alpha" keys and it accepts those and=20
produces the characters, so I know the underlying code is working.

The full USB HID scancode list is here: =20
http://www.freebsddiary.org/APC/usb_hid_usages.php

Anyone know how to get these events recognized, or have any other=20
"innocuous key" suggestions?

Thanks in advance for any insights!



Joe Koberg



---------- JALv2 Code -----------------------

    include 18f2553

    pragma target PLLDIV        P1          -- divide by 1 - 4MHz crystal
    pragma target CPUDIV        P2         -- Divide 96MHz PLL by 2 for CPU
    pragma target USBPLL        F48MHZ      -- Use PLL for USB
    pragma target OSC           XT_PLL      -- Low-speed crystal with PLL.
    pragma target clock         48_000_000

    include usb_keyboard

    const USB_KEYBOARD_KEY_VOLUME_UP =3D 0x80
    const USB_KEYBOARD_KEY_VOLUME_DOWN =3D 0x81

    enable_digital_io()

    usb_keyboard_init()

    while( !usb_is_configured ) loop
    end loop

    var dword counter

    forever loop
         usb_keyboard_flush()
         if( usb_is_configured() ) then
             counter =3D counter + 1;
             if( counter > 10000000 ) then
                 counter =3D 0
                 ush_keyboard_send_key(0x00, USB_KEYBOARD_KEY_VOLUME_UP)
                 usb_keyboard_flush()
                 ush_keyboard_send_key(0x00, USB_KEYBOARD_KEY_NONE)
                 usb_keyboard_flush()
                 ush_keyboard_send_key(0x00, USB_KEYBOARD_KEY_VOLUME_DOWN)
                 usb_keyboard_flush()
                 ush_keyboard_send_key(0x00, USB_KEYBOARD_KEY_NONE)
                 usb_keyboard_flush()
             end if
         end if
    end loop












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