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Thursday, April 23, 2009

How to manually update BB0703(PICkit 2) Operating system?

Author: Chaonan Chen, Huihui Duan, Au Group Electronics

There is very few opportunity ever since the PICkit 2 V2.4x release for a PICkit 2 losing a OS. However it still happens from time to time even in a very very small possibility. When this is happening the PICKit 2 will blink the red LED indicating there is no functioning OS. To get the PICKit 2 back to normal, a new PICkit 2 OS needs be manually downloaded into the PIC18F2550 chipset.

The following tutorial is a step by step guide on how to manually upgrade the PICKit 2 OS. It also answers the following frequent asked question.

Question Asked:
What does it mean when the Busy LED (on PICKit 2) flashes once per second without pushing and holding the button while BB0703 is connected to a USB? How do I correct this?
Answers from Au Group Electronics:
The Busy LED blinking means the unit is in the bootloader mode. For a normal unit, pushing and holding the button while connect BB0703 with USB will manually force the BB0703 (PICkit 2) entering bootloader mode.
To bring the BB0703 (PICkit 2) back to normal programming mode, PICkit 2 Operating System needs to be downloaded from the “PICkit 2 programmer” software. Here is the step by step instruction:
Step 1. Disconnect BB0703 with PC if it was connected before.
Step 2. Open PICkit 2 application software.
Step 3. Connect BB0703 with PC.
Step 4. On "PICKit 2 programmer software", select "Tools-->Check Communication"
"The PICKit 2 has no Operating system. Use the Tools menu to download an OS." will display (figure 1) and the software will be locked up.

Step 5. Disconnect BB0703, this will unfrozen the software.
Step 6. Connect BB0703 back to PC, then click "Tools-->Download PICkit 2 Operating System" (Figure 2)

Step 7. Select the file name "PK2V023200" (assuming V2.61 is used. for other V2.xx, file name should be similar), click OPEN (figure 3)

It will then automatically download the OS into BB0703 (PICKit 2), wait the unit finish the downloading process.

Step 8. Click "Tools-->Check Communication", now it should back to normal mode.

In the V2.5x and V2.6x firmware, there is a self-test safety check feature, if something found wrong on firmware and configuration bits, the unit will be forced entering the bootloader mode thereafter.

A few searches on Microchip Forum provides more background information as the following link.

It is a good practice to leave the unit on the USB port whenever possible.


  1. Very usefull. I got back in life my pickit2!!!

  2. Hi every body,
    i m facing the same problem as discussed in pickit2 FAQ; E: Windows Error: Unrecognized USB Device, i want to know the solution for this. Kindly anybody help me plz to come out from this headache,,
    best regards

  3. Try reprogram the 2550 chip using another PIC programmer.

    The best practice is: having two PICkit 2 around, when one is suffering the firmware or configuration bit corruption, you can always using a working one to bring the malfunction unit back.

  4. thank you this was very helpful.just saved regards

  5. thank you Au Group Electronics!!!!!!!

  6. Information is helpfully. Thank you. I'm also fixed it the same problem.


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