Fuse-Bits
The Fuse-Bits represent the main switchboard of the AVR, so to speak. They are used to set the basic settings that should be available before the start. Therefore Fuse-Bits cannot be changed from the normal program, but are set by the programming device when the AVR is burned. The only exception: self-programming of the AVR with the help of the boot loader.
The Fuse-Bits can be used to set whether the AVR should be clocked by the internal RC oscillator; you can set an external quartz as the clock source and optimally adapt the oscillator behavior, but you can also choose an external oscillator as the clock source. You can also use the Fuse-Bits to change the function of certain pins and more.
Since the Fuse-Bits can fundamentally change the functioning of the AVR, they (with exceptions) do not take effect immediately after they have been burned - it must not happen that the AVR suddenly no longer reacts to the burning device. Therefore, after changing the Fuse-Bits, you have to carry out a PowerDown sequence, i.e. switch the operating voltage off and on again.
Changes to the Fuse-Bits should only be made with care. The following Fuse-Bits can lead to errors that the AVR can no longer be burned:
1. M- CKSELO, CKSEL1, CKSEL2 and CKSEL3 change the clock source
2. RSTDISBL switches off the RESET pin
The configuration of the Fuse-Bits is supplied by us.