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Support Forum » Setting Fuses
January 13, 2011 by n3ueaEMTP |
I've decided to venture into the world of ISP programmers without a bootloader. Trouble is, all of my programs use the fuse settings that my initial ATMega168 came pre-programmed with (from NerdKits). Here is my question: Will the following makefile work?
How would I handle this?
Can they both be there, separated by some punctuation, or will just one suffice? Any help will be appreciated!! Thanks Chris B n3ueaEMTP |
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January 14, 2011 by Rick_S |
Honestly, I program the fuses independantly. I don't place that in the makefile at all. The reason they are in the makefile for the foodloader is because that is expected to be run once when setting up a chip. After the fuse are set, there is no need. I don't know if you've researched what those fuse settings do or not, but this is what they mean.
The fuse settings as they are will work fine for an ISP loaded program. The only problem is you can overwrite the bootloader section via ISP because the bootloader is only protected in self program mode. Rick |
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January 14, 2011 by Rick_S |
Just remember, that you will have to have a crystal in the circuit when programming the fuses like this other wise, the chip will not operate. |
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January 14, 2011 by n3ueaEMTP |
Rick, thanks for getting back to me. My end goal is to program the MCU once and not program it again so a bootloader is not necessary. So far, I've programmed the fuses and then put the program on the MCU. I'm just wondering if I can combine setting the fuses and the actual programming of the MCU. Thanks again Chris |
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January 14, 2011 by Ralphxyz |
Why are you needing to (re)set the fuses? Once I load the bootloader I then just flash any new program and never even think about the fuse settings, am I missing something? I always try to practice "just because you can do something doesn't mean you should". Ralph |
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January 14, 2011 by n3ueaEMTP |
Ralph, excellent point. My goal is to flash the MCU once and only once. My main project is a system for preforming tasks when firemen get emergency calls (Turning on lights, opening & closing garage doors, etc) so once it's flashed, it goes on the PCB, gets installed at a fire company and never gets thought about again. My prototype MCU will only get the fuses set once. |
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