USB Help

[Jerry I]

Hi

I have never used a Pic with USB so I am trying to learn.

Just compiled the USB Keyboard Example ex_usb_keybord.c

Set The CPU type to USB_HW_MCHP_18F14K50 in ex_usb_common.h.

All compiles fine with Version PCH v4.132.

Hardware like this:
Used 12Mhz Crystal connected D+ & D- to USB Connector.
Pullup on MCLR.
Serial RS232 connections.

Example starts, Intro screen shown as in code via RS232
'CCS HID Keyboard Demo. ......

Last Line shows USB Connected, waiting for enumaration.....

I have it connected to Win7, Device manager shows under keyboards:

HID Keyboard Device

At this point I'm lost. ????

Waiting for enumeration..... ???? rest of demo not working.

Thanks in advance for any help.

[Ttelmah]

Two things:

Capacitor from Vdd to Vss right next to the chip. Something with good HF performance (polyester/ceramic for example, not an electrolytic).
Similar capacitor from Vusb to Vss. I suspect this is the critical one you are missing. Without this, USB won't work. 330 or 470nF polyester.

Best Wishes

[Jerry I]

Thanks Ttelmah for quick answer.

Your were right I did not have a capacitor Vusb to Vss.

I did add capacitors as you suggested, but still does not work.

Any other ideas.

Thanks