How to make a driver under QNX?

Hi, I need to make a driver under QNX but I dont know how to start.
Can anybody give me some source code of drivers examples?

Thank you …Ohmio

I can’t download the DDK source codes from myqnx site because I haven’t got the serian and password to enter

What kind of driver?

Have you purchased your QNX?
I don’t think DDK is available to “free” QNX users.