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problem on using avr fuse bits

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arash_micro

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Hi all.
I was working with bascom and it's programmer.
I change the fuse bits (internal rc to external oscilator) and program it, but afther this
i couldent program any more.It seems to be locked.But "RESET CHIP" button dosent work.
How can i solve this problem (Reseting My ATMEGA16).
Thank you.
 

you cannot program the chip with ISP anymore, hence you should use the other way: parallel high voltage programming (is this the correct term?)

refer to the datasheet for details. otherwise, just buy another chip ;)
 
Your problem is that your chip is waiting for the external oscilator to start working :D it doesn't work anymore from the internal oscilator. You can attach a crystal to the chip and program the fuse bits to internal oscilator again, then you can remove the crystal again.

Shereef
 
I had this problem for some Atmel MCUs, especially when it is first flashed.

One way is to use a jumper wire to short the XTAL input (usually side by side pins of the QFP package) to any kind of clock source, best from a crystal output or another chip's clock input.

It fools the programmer that the MCU is provided an external clock source, so it will allow you to program the MCU (with fuses set to use internal clock and reset delay of the MCU).
 
ezshereef said:
Your problem is that your chip is waiting for the external oscilator to start working :D it doesn't work anymore from the internal oscilator. You can attach a crystal to the chip and program the fuse bits to internal oscilator again, then you can remove the crystal again.
Shereef

hi
yes, your problem is external clock.
just attach a crystal to the chip.
regards
 
You must use an external oscillator. Adding the crystal alone will not help you.
You have two possibilities:
1. Make a simple oscillator using 555. Frequency is not so important but try with 1 MHz
2. If you have another board with microcontroller use its clock as the source. Connect clock output from this board to the clock input of your board.
Hope this will help you.

Pop
 
You must use an external oscillator. Adding the crystal alone will not help you.

i've tried it before and worked for me.
Just give it a try you won't loose anything :)
 
Thank you all guys .I solved my problem with your helps.
 

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