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SLF
Joined: 22 Sep 2008
Posts: 6
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| Change fuses |
 Posted: Mon Dec 08, 2008 11:08 am |
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Hi together!
I need to change the fuses during my program between HSPLL and INTHS with a PIC 18F2550, because of the power consumption.
In HSPLL mode I need the USB in FullSpeed with a 20MHz Osc (PLL5) and CPUDIV1.
In INTHS I need only the Internal Oszillator with 2MHz.
I this possible to do?
I tested this code, but I think it doesn't work:
Switch to HSPLL:
| Code: |
read_configuration_memory(0x300000,data,12);
bit_set(data[1],0);
bit_set(data[1],1);
bit_clear(data[1],2);
bit_set(data[1],3);
write_configuration_memory(data,0x300000,12);
setup_oscillator(OSC_2MHZ);
#asm
BSF 0x0F6F.2 // FSEN
#endasm
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Switch to INTHS:
| Code: |
read_configuration_memory(0x300000,data,12);
bit_set(data[1],0);
bit_set(data[1],1);
bit_clear(data[1],2);
bit_set(data[1],3);
write_configuration_memory(data,0x300000,12);
setup_oscillator(OSC_2MHZ);
#asm
BcF 0x0F6F.2// FSEN
#endasm
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My compiler version is 4.073 |
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Ttelmah
Guest
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| Posted: Mon Dec 08, 2008 11:29 am |
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Problem is that most fuses, are only read when the chip boots up.
Remember also, that the write life of the configuration memory, is relatively limited. Not a problem if you change a bit every few weeks, but a major problem if you change it more often....
Don't do this.
Use the chips oscillator switching ability instead. This is what it is there for...
Look at the options in the setup_oscillator command.
Best Wishes |
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SLF
Joined: 22 Sep 2008
Posts: 6
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| Posted: Thu Dec 11, 2008 4:25 am |
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Thanks a lot!
That's much easier and it works now fine! |
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