Win XP can't install driver for USB HID

[spom]

Hi everybody,

I have a little problem with using HID USB.
I use the PIC 18F4550 with a 4MHz crystal and the example code "ex_usb_hid.c". I changed the clock to 4000000 an comment out #if and #elif parts so that I have

[Ttelmah]

It won't, because your system is not running a legitimate frequency.
The USB circuitry, _must_ run at 48MHz.
With 4MHz in, you need to select 'PLL1', so the incoming clock is not divided before being fed to the USBPLL circuit. Then the 4MHz, is multiplied by 24, to give the 96Mhz master clock for the USB stages. This is then divided by 2, to feed the USB clock. Currently, you are trying to run the USB at 9.6MHz...

Now, do you really want to run the main CPU at 4Mhz?. This is low, and _may_ give timing problems with handling some of the USB transactions fast enough. Your choices are:

XT (not HSPLL) and CPUDIV1 - gives 4MHz for the CPU (clock=4000000)

XTPLL and CPUDIV1 gives 48MHz for the CPU (clock=48000000)

XTPLL and CPUDIV2 gives 32MHz for the CPU (clock=32000000)

XTPLL and CPUDIV3 gives 24MHz for the CPU (clock=24000000)

XTPLL and CPUDIV4 gives 16MHz fo the CPU (clock=16000000)

Or you can use the internal RC oscillator to run the CPU (but _not_ the USB).

Personally, I'd suggest you will find operation more likely to work properly, using XTPLL, CPUDIV4, and the 16Mhz operation. 4MHz, is 'pushing it',for USB. If you are not doing anything 'timing critical' in the main processor, then selecting INTRC, and running the CPU at 8Mhz is another good option (you will still need PLL1, and the 4Mhz crystal, to run the USB circuitry).

Best Wishes