Bulk Erase with the ICD-U40

DaveThib · Joined: 17 Oct 2004 Posts: 15 Location: New Hampshire USA

I am having difficulty erasing a Copy Protected part. I have been working on this product for months and yesterday I changed the fuse from NOPROTECT to PROTECT since I am about to send this off to a trade show. I want to make a few more changes and I found that I cannot reprogram the part. Upon reading up on this in the datasheet, Microchip's site and this forum, it it appears that I need to use the ICD program and set it for Bulk Erase. Well I did that and it still gives me varification errors and configuration errors. It says it is PROTECTED.
What am I doing wrong?
I am using PCW as my programming/debugging enviroment and I have the ICD-U40. I did just use the ICD program for the first time yesterday and read about its use. I am programming a PIC16F87. I have the NOLVP fuse set and I do not have B3 wired up. In the ICD software I see the erase mode set to BULK. When I download to the PIC I find the hex file that I compiled with PCW that now has the NOPROTECT fuse set and it does not load the program and gives the errors.
What am I missing?

newguy · Joined: 24 Jun 2004 Posts: 1907

The only thing that comes to mind is the power supply. You can only perform a bulk erase if the chip has a 5V supply.

Hope this helps.

DaveThib · Joined: 17 Oct 2004 Posts: 15 Location: New Hampshire USA

I am using a 5V power rail. It is sitting at 5.06 according to the volt meter on my O'scope screen. The device is being powered by its own power supply not the ICD. The MCLR line has a 47K pull up and a .01uf cap. The part was programming just fine with no errors. It has been perfectly reliable until I set the copy protect fuse now I can't reprogram it. Very frustrating!

newguy · Joined: 24 Jun 2004 Posts: 1907

http://www.ccsinfo.com/forum/viewtopic.php?t=21016&highlight=protect+erase

Do a search using the terms "protect" and "erase". Apparently you aren't the first to have issues with this.

Guest · Posted: Thu Jan 19, 2006 1:12 pm

Thanks for your help in trying to find this answer. I must be doing something stupid but I have no idea what. The topics in the forum you suggest all are dealing with the problem of not being able to change the fuses while running at 3.3v. The answer is to run it at 5v. Well I am running it at 5v. I seem to be doing everything I am supposed to be doing. I am using the TSSOP version of the PIC so it is not a simple thing to replace the processor.

DaveThib · Joined: 17 Oct 2004 Posts: 15 Location: New Hampshire USA

Well I contacted Microchip support to make sure there was not something I missed in the datasheet. Here is their response:

Below is a response from Microchip Engineering Support Team for your submitted ticket #: 1-39072
A description of the problem and our proposed resolution is contained below.

Area: PICmicro Products
Product Group: PIC16F8X
Product: PIC16F87

Problem Resolution:
You are right about several things. The bulk erase must be executed to the device in order to re-set the code protect bit, and of course, this takes 4.5V or better ( up to 5V ) so Low Voltage Programming should be disabled.
I can't support CCS tools, only Microchip tools. If you have access to a Microchip programmer, or the ICD2
you could erase this device.

END OF MICROCHIP RESPONSE

I guess I am getting the run around. I will ask the CCS folks next since nobody so far has run into this problem.