Author Topic: help reading fuse settings from datasheet  (Read 2953 times)

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Offline vidamTopic starter

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help reading fuse settings from datasheet
« on: March 31, 2008, 07:33:40 PM »
Hi all,

I am reading this datasheet on atmega 2561 to find out how to set the fuses properly.

Table 6 on page 4 states the following.

Table 6. BOD fuse configuration on ATmega1281/2561
BODLEVEL 2..0 | Typical VBOT [V]
111 | BOD disabled
110 | 1.8
101 | 2.7
100 | 4.3

The options inside of AVR Studio 4 are:

Brown out detection disabled; [BODLEVEL=111]
Brown out detection level at VCC=1.8 V; [BODLEVEL=110]
Brown out detection level at VCC=2.7 V; [BODLEVEL=101]
Brown out detection level at VCC=4.3 V; [BODLEVEL=100]

On-Chip Debug Enabled; [OCDEN=0]
JTAG Interface enabled; [JTAGEN=0]
Serial program downloading (SPI) enabled; [SPIEN=0]
Watchdog timer always on [WDTON=0]
Preserve EEPROM memory through the Chip Erase cycle; [EESAVE=0]
Boot Flash section size=512 words Boot start address=$1FE00; [BOOTSZ=11]
Boot Flash section size=1024 words Boot start address=$1FC00; [BOOTSZ=10]
Boot Flash section size = 2408 words Boot start address=$1F800 [BOOTSZ=01]
Boots Flash section size = 4096 words Boot start address = $1F00; [BOOTSZ=00]; default
Boot reset vector Enabled (default address=$0000); BOOTRST=0
Divide clock by 8 internally [CKDIV8=0]
Clock output on PORTE7 [CKOUT=0]
Ext. Clock; Startup-time: 6 CK + 0 ms

rather than type out the rest of the fuse options here is the photo

What is the best way to interpret the datasheets to figure out the fuse settings I must set?

« Last Edit: March 31, 2008, 07:55:29 PM by vidam »

Offline superchiku

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Re: help reading fuse settings from datasheet
« Reply #1 on: March 31, 2008, 10:25:18 PM »
hey man setting up fuses is same as changing some address registers , u just need to know which one there are 2 type of fuse byte, LOW and HIGH , so look in ur datasheet which tells u what u should change for the appropriate fuses to be changed and to let the other fuses unaltered

also see this site
« Last Edit: March 31, 2008, 10:27:35 PM by superchiku »



Offline dunk

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Re: help reading fuse settings from datasheet
« Reply #2 on: April 01, 2008, 02:50:10 PM »
hey Vidam,
so as i read in another post of yours, you have already noticed it's easy to brick your device in a careless second when setting your fuse bits....
we have all done it. and will do so again.

the strategy i usually take is from a working device first read your current fuse bits. (the "Read" button in your picture.)
only change the bits that you understand.
then write them back to the device. (the "Program" button in your picture.)

in using the working set as a template i find less likely to make typos in my fuse bits.

but yea, using the datasheet is your best bet.
it will usually tell you what the default settings of your device are and it's useful to compare these to the fuse bits you read off your new AVR just to make sure you have it straight in your hed.



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