SparkFun Forums 

Where electronics enthusiasts find answers.

Your source for all things Atmel.
By curtcarpenter
The Velleman Kit K8055 USB experiment board is available from a number of sources on the internet, is not too expensive (around $50), and gives you the capability to use a USB port to "talk" to the outside world from within your own programs. It offers both analog and digital I/O capability, albeit at low bandwidth.

I've used this board as the basis for a very simple "bit-banger" programmer for several ATMEL uCs, and have been told that my K8055-based approach is more reliable (although a lot slower) than the popular parallel port cable scheme.

If you'd be interesed in the hardware/software to build a K8055-based programmer, let me know and I'll be happy to share my code and hardware design here.
By simonvav
It is not difficult to build your own programmer for PIC18F24J50. I built one from MCP2200. Then you only have to use USB framework to get PIC to talk over USB and there is still a lot of space to write own functions. I wrote two functions that gave me direct control of PIC registers via USB. Now, I can use whole PIC functionalory like 10-bit A/D (up to 12 input channels) directly from a PC. This is a great way of testing your algorithms. Later on you may also program them in the microcontroller.