Read FUSE bit and modify without effect any damage to program space

Thread Starter

micropad

Joined Dec 24, 2011
75
Dear All
Have a nice day

I need read the fuse bits of PIC18F2550 and modify it and to be re programmed without any damaged to the program space

Please advice about programmer and software

Thanks in advanced
 

Thread Starter

micropad

Joined Dec 24, 2011
75
Source code can not be given to end user


If I want to do improvements and new release

I should need to know, it should possible or impossible ?
 
Last edited:

jpanhalt

Joined Jan 18, 2008
9,771
Source code can not be given to end user
Are you the end user or the manufacturer? Setting the appropriate fuse protects the source code from the end user. If you are the manufacturer/IP owner, then you should have that code. Do you or your company own that code?
 

Thread Starter

micropad

Joined Dec 24, 2011
75
Our Company is the legal owner of the code and I too have them
Currently we provide hex code to the our technical staff to upload the code to the end user location . but company is requesting to find the solution upgrade firmware some other way without giving to technician
 

Papabravo

Joined Feb 24, 2006
13,958
Our Company is the legal owner of the code and I too have them
Currently we provide hex code to the our technical staff to upload the code to the end user location . but company is requesting to find the solution upgrade firmware some other way without giving to technician
  1. Disassemble the hex code
  2. Create new assembly language source files from the disassembly listing
  3. Modify new source files to suit your requirements
  4. Assemble the new source files
  5. Program new or update existing parts from new hex files
Easy peasy, for an accomplished firmware jockey like myself. Having done it several times helps.
 

Thread Starter

micropad

Joined Dec 24, 2011
75
  1. Disassemble the hex code
  2. Create new assembly language source files from the disassembly listing
  3. Modify new source files to suit your requirements
  4. Assemble the new source files
  5. Program new or update existing parts from new hex files
Easy peasy, for an accomplished firmware jockey like myself. Having done it several times helps.
I have source code
 

Papabravo

Joined Feb 24, 2006
13,958
I have source code
Then I fail to understand your problem. You modify your source code and reflash the part. In order to do that the code protect bits must be reset by a bulk erase. That is their whole purpose in life, to prevent those without the source code from doing what you describe.
 

Thread Starter

micropad

Joined Dec 24, 2011
75
Then I fail to understand your problem. You modify your source code and reflash the part. In order to do that the code protect bits must be reset by a bulk erase. That is their whole purpose in life, to prevent those without the source code from doing what you describe.
Is there any hex upload procedure by end user without reading code in side the MCU
 

be80be

Joined Jul 5, 2008
2,047
Bootloader then in user can load firmware themselves. Bootloader can be made to read firmware to load so as
user can't. crypto-Bootloader
 
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