Questions tagged [fuse-bits]

Fuse (and Lock) Bits are a type of low level programming and security feature on embedded devices. Most popularly known in Atmel AVR devices, they can be likened to a secure Bios on a computer. They can also be found in MSP430, PIC, and other microcontrollers. Care needs to be taken when working with programming Fuse Bits, as they can render a device useless. MANY are One Time Programmable.

Fuse (and Lock) Bits are a type of low level programming and security feature on embedded devices. Most popularly known in Atmel AVR devices, they can be likened to a secure Bios on a computer. They can also be found in MSP430, PIC, and other microcontrollers. Care needs to be taken when working with programming Fuse Bits, as they can render a device useless. MANY are One Time Programmable.

A common security move chosen by consumer technology manufacturers is to use fuse bits to prevent downgrading firmware. Microsoft's Xbox line, Sony's Playstation line, BluRay players, and HDMI capable devices are known to do this. Many Printer and Ink Manufacturers use eeproms that have these features, much to the detriment of their consumers.

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What are Atmel Fuses?

What are Fuses in Atmel microprocessors and when I should or need to change the default settings?
tuupola
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How do I set the clock speed fuses on an ATtiny85 when using an Arduino as a programmer?

I'm following this tutorial, programming the ATtiny85 with an Arduino, using it to play some tones (through a piezo speaker). I'm struggling with getting the tones at the right pitch (I'm creating the wave forms manually, as the tone() function is…
fearoffours
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Recovering an ATtiny13

I am playing with an ATtiny13 and I thought it would be good to use it with an external 8Mhz ceramic oscillator instead of the 1.2 Mhz built-in one. (I want to do a soft-uart at 9600 bps, so I figured 1.2 Mhz was too slow) To change to an external…
Stefan Arentz
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ATTiny85 not working after burning bootloader

I am having a problem with my ATTiny85. I should mention I use Arduino as an ISP to program it. My ATTiny worked fine until I decided that I need to step up the clock speed from 1MHz to 20MHz so I selected ATTiny85 at 20MHz from the Boards menu and…
Calin
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What is an eFuse

I heard in a recent presentation that the XBox 360 uses an eFuse to prevent users from reverting back to prior boot/firmware image. What is an eFuse and how do they work?
Scott
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Does CKDIV8 save battery life when programmed?

On ATmega328P there is a CKDIV8 fuse bit that when programmed divides clock by 8. I'm wondering if the power consumption is equal on these two setups: micro with 8MHz external crystal and CKDIV8 fuse bit programmed micro with 1MHz external crystal…
Darkhan
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ATmega32u2 fuse bits - can destroy using FLIP?

I want to build some simple application using ATmega32u2, and have it programmed strictly only via USB, by using the factory-builtin USB bootloader on µC, together with the "FLIP" program running on Windows computer. I've read, that in ATmega32u2…
akavel
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Fuse Bit settings in ATmega128 Micro controller

I am working with ATmega128 board. The datasheet states ATmega128 is by default shipped in ATmega103 compatibility mode In ATmega103 mode, the MCU both serial communications cannot be used and even some IO port operations are restricted. I want…
Sanju
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Why does my Atmega328 clock seem to be off by a factor of 2?

I have an Atmega328 chip I am trying to debug. I have a sketch that blinks an LED and echoes back things received over the RX/TX pins. I am using the "Import Arduino Sketch" feature in Atmel Studio 7. I want to use the internal 8 MHz clock. The…
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How to test a CPU watchdog on board?

The watchdog of an ATMEL ATXMega128 should have been enabled with fuses. It triggers a reset, if the timer was not reset within the configured time span. I want to be sure, that it is enabled and working properly. What is a good method to verify…
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ATmega32 factory reset board

Is there a reset board available (I mean schematic, link, tutorial or anything else) out there for the ATmega32 microcontoller (I heard about a high-voltage reset board, and I found some links for an ATmega8 reset board, but not ATmega32)? I…
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ATMega8U2 and DFU mode

I made simple board with ATMega8U2 microcontroller for my USB experimenting (I'd like to make MIDI, HID, ... devices). I took inspiration in Arduino Uno. If you look on schematic below, you can see it is almost the same as Uno. I programmed 8U2 with…
vasco
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ATmega fuses for external crystal oscillators greater then 8 MHz

Currently I am trying to figure out what the correct fuse settings for my ATmega8 are, when I want to use an external crystal oscillator with a frequency greater then 8 MHz. I have found the following table in the Atmel ATmega8 datasheet (p.…
PetPaulsen
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Do I have to use external clock for ATmega ISP programming after changing fuse bits?

After programming an ATmega microcontroller via ISP (SPI) interface and changing the clock-related fuse bits, I'd like to reprogram it again. Will I have to connect it to an external clock now to do so, or will I always be able to program it by…
akavel
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Why does my AVR act weird (resets, data corruption) when receiving a few bytes on the UART?

I have an ATmega644 connected to another device using the UART. After receiving a few characters on the UART the device resets and/or acts weird. Some examples of this behavior: Code before the main loop is executed again but MCUSR is 0 (i.e. no…
ThiefMaster
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