ASM51

9. I get 'USB device not recognised', what should I do?

This problem is often reported by PICkit 2 users. I don't have a definitive solution, but some thing seem to help:

disconnect the PICkit 2 from the target circuit before you connect the USB cable
plug the USB connector in slowly (this increases the time between the power contacts connecting and the data contacts connecting)
when you get the error, disconnect, wait a few seconds, and reconnect.
contrary to the above, some people have reported that you must wait a long time (>30 seconds?) before you attempt to reconnect. I suspect that this is a cure for a different problem.
if the PICkit 2 is connected to a HUB, disconnect the HUB from the PC and reconnect (I still saw the 'USB device not recognised' error but the device did work!)
(a bit experimental) during experiments with a PICkit 2 clone I am designing I noticed that the 'USB device not recognised' was produced by the PICkit 2 application, never by the bootloader, and also never immediately after the application was downloaded and started by the bootloader. The USB part of the application and bootloader work a bit different, so I reasoned that maybe the bootloader does a better job on the USB initialisation. But the original bootloader does not initialise the USB, except when no application is present, or the button is pressed. So I modified the bootloader to *always* initialise the USB, wait a second, shut down the USB, and then start the application (if present). You can hear this: when you plug it in you hear a USB attach, USB detach, and a final USB attach. So far I never got the 'USB device not recognised' with this modified bootloader. To use this bootloader you will have to re-program your PICkit 2. When you open it you will notice a strip of 6 pads at the edge of the PCB. These pads can be used to (re) program the 18F2550 in the PICkit 2 with .... a PICkit 2. Here are the files: PICkit2Bootloader_Wouter.hex and boot_main.c.