Programming the PIC18F6722

Shown above is the programming pod that I use and have found to be very reliable. Due to space limitations (as well as a lack of knowledge at the time) the TinyCNC-II has a fairly non-standard programming pin configuration. I made an adapter cable from a piece of old ribbon cable and soldered some connector pins to the individual wires to make a cable that gets the job done. If this causes you any teeth gnashing then I do apologize but I hope that the above pictures are enough to get you over the hump.

The pins are a rather snug fit but have not failed (yet) to reprogram the CPU literally hundreds of times for testing, correcting problems and adding new features. The Pickit-3 powers and programs the CPU without the need of an external power supply. Finally, the sixth hole position has no connection installed as that is for a low voltage programming process that I do not use in this project.

Step #1

Connecting to the TinyCNC-II Board.

Step #2

Set Software for Fast Programming.

Step #3

Set for Verify and Clear Memory.

Step #4

Erasing the CPU.

Step #5

Loading the TinyCNC-II Hex File.

Step #6

Hex File Loaded and Ready.

Step #7

CPU Successfully Programmed.

Step #8

Program Verified in the CPU.

Step #9

Connect a 9 Volt Battery Across the 33 Volt Zener Diode to Test.

The series of pictures above show the steps involved in using the Pickit-3 programming software from Microchip to program the PIC18F6722 CPU.

If you first bring up the software and it does not correctly read the chip ID as a "PIC18F6722" (as pictured in the first of the nine pictures above) then there is something wrong with the CPU hardware section of the PCB or the settings in the programming software are not correct.

Please review each panel to ensure that your software is set up the same. If it reads the CPU ID properly you should have no issues programming the CPU.