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asherc
Joined: 21 Apr 2010
Posts: 4
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| fuses explanation please |
 Posted: Thu Apr 22, 2010 10:27 am |
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Hello, I am playing a bit of a guessing game with the fuse settings i need.
In the ccs manual it says:
| Code: | Syntax:
#fuses options
Elements:
options vary depending on the device. A list of all valid options has been
put at the top of each devices .h file in a comment for reference. The
PCW device edit utility can modify a particular devices fuses. The PCW
pull down menu VIEW | Valid fuses will show all fuses with their
descriptions.
Some common options are:
· LP, XT, HS, RC
· WDT, NOWDT
· PROTECT, NOPROTECT
· PUT, NOPUT (Power Up Timer)
· BROWNOUT, NOBROWNOUT
Purpose:
This directive defines what fuses should be set in the part when it is
programmed. This directive does not affect the compilation; however, the
information is put in the output files. If the fuses need to be in Parallax
format, add a PAR option. SWAP has the special function of swapping
(from the Microchip standard) the high and low BYTES of non-program
data in the Hex file. This is required for some device programmers.
Some processors allow different levels for certain fuses. To access these
levels, assign a value to the fuse. For example, on the 18F452, the fuse
PROTECT=6 would place the value 6 into CONFIG5L, protecting code
blocks 0 and 3.
When linking multiple compilation units be aware this directive applies to
the final object file. Later files in the import list may reverse settings in
previous files.
To eliminate all fuses in the output files use:
#FUSES none
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Is this supposed to help me decide what fuses I need? If so how? I was
kind of expecting like a list of the fuses with a decent explanation of what
each and every one of them are, what it means, how it relates to the
datasheet, what registers are altered, considerations for use and all other
useful information. I can't find anything useful in the above or in the
device.h. Where is this pull down menu? I am using mplab ide sim.
cheers |
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dyeatman
Joined: 06 Sep 2003
Posts: 1933
Location: Norman, OK
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| Posted: Thu Apr 22, 2010 11:21 am |
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The fuses are defined by Microchip and change from device to device. You
must read the data sheet to get the detailed info on what the fuses do. It is
really not CCS's job to keep up with all that, they just need to provide a way
to set the desired fuses in the compiler.
The drop down they refer to is in the CCS IDE, not MPLAB. If you have the
IDE there is a fuses.txt file in the PICC compiler directory that provides
some descriptions of the fuses but you still have to use the data sheet and
some homework to determine the ones you need for your application..
_________________
Google and Forum Search are some of your best tools!!!! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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asherc
Joined: 21 Apr 2010
Posts: 4
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| Posted: Thu Apr 22, 2010 2:07 pm |
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Thanks for the comments and what you say would be fine and dandy if the names of the fuses related to the modes described in the datasheets, or if there was a fuses.txt that included for example h4_sw = hspll for example. Thanks for the pointer to the file.
cheers |
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