So, it is a detective story. (Note that, despite my cryptic screen name, I am actually the world's greatest detective, Hercule Poirot
I hope that the following clues suggest a plan for using your "little gray cells" to solve your problem. I start with the first clue, gleaned from your data sheet and articulated by mbrowing. Most of the remaining clues would be obvious to any motivated party, once you get started. I give additional help with one link that might be difficult to come by for any other than the world's second-greatest or third-greatest detective.
- Get the Data Sheet for the PIC18F4550.
- Download and install the current version of MLA (Microchip Libraries for Applications).
- Look under the MLA distribution apps/usb/device directory for projects that have firmware directories for the picdem_fs_usb board. (This is the old FSUSB board that has a PIC18F4550.) For example:
- Make sure that you can build that unmodified project under MPLABX. I suggest that you start with the latest version of XC8.
- Find the Microchip web page for the old FSUSB board and download the documentation.
Heck, I'll give it to you:
Old FSUSB Board User's Guide
Look at the schematic to see how its connections are used in the MPLABX project. Study the code and see if the USB parts make sense.
- Create a new project (or, maybe modify the one you started with) and make changes to take into account the differences between the PICDEM board and your Tinkerer's Special.
From this point, the story has transmogrified from the level of a classical Hercule Poirot
mystery to a brand new Car Chase/Big Explosion Action story. Not quite on the level of Mission Impossible
, but it can be exciting.
If you have problems:
I think that it is very possible that you won't get much direct help for your particular chip, but if you have any general questions, you can post specific
details about your progress and specific
questions about what the sticking point is.
Enjoy your adventure!