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Noting responds when sending integers trough my UART

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pascalbythree:
https://www.engbedded.com/conffuse/

Is there also a button that i should not press, to lock my MCU to be programmed again?

since nothing is marked with RED areas.

ccrause:

--- Quote from: pascalbythree on December 02, 2023, 02:25:40 pm ---https://www.engbedded.com/conffuse/

Is there also a button that i should not press, to lock my MCU to be programmed again?

since nothing is marked with RED areas.

--- End quote ---

All the fuse settings can under some circumstances cause problems.  Below some fuse bits that may cause problems:

* Do not set the clock source (SUT_CKSEL) to external clock, unless you have an external clock/crystal correctly connected to the chip.
* Do not disable SPIEN, you will not be able to program the chip via SPI.
* Do not enable BOOTRST, the controller will then jump to a bootloader memory address - unless you have a bootloader at the correct location this may cause issues.
* Do not disable the reset pin, leave RSTDISBL unselected.
* Do not enable watchdog timer (WDTON), the controller may spontaneously reboot.
* Do not enable debugwire (DWEN), SPI programming will not work even if enabled. If you want to do onchip debugging, you have to enable this, but read up on how to disable DWEN again.
* Be careful when setting a low voltage for brownout detection (BODLEVEL), if too close to your supply voltage a sudden power dip could cause a reset.  But if you have a potentially weak power supply (such as a coin cell battery that can die) you should consider activating BOD to prevent malfunction at low voltage.
You can of course change any fuse bit to tweak some functionality, but you must know what will happen when you change it.  Your code must be written with the fuse settings in mind (for example you need to know whether the internal oscillator is used and whether the divide by 8 bit is set).  Although this sounds serious, just take care and focus. Don't guess fuse values, always check fuse values against either the datasheet or a fuse calculator site before programming fuses.

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