doubt about system clock speed for atmega32L.

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simpsonss
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Posted by simpsonss: Tue. May 5, 2009 - 03:05 AM
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:?:
hi all,

i have a doubt about the system clock speed for atmega 32L which mention in some of the tutorial or discussion.
i'm using atmega32L for my learning. so i add in a 4Mhz XTAL and coupling cap with it. From the datasheet, i know the maximum speed of atmega32L is 8Mhz. (correct me if i'm wrong). so after i add in the 4Mhz XTAL is it means that my system speed is 4Mhz now? because i'm not sure what is the input frequency i'm using when calculating the timer target count value.

thank you.

Tags:

AVR Microcontrollers, megaAVR and tinyAVR, ATmega32
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glitch
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Posted by glitch: Tue. May 5, 2009 - 03:14 AM
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no, you must also set the fuses accordingly to tell the mega32 to use that crystal. Otherwise it will be running off the internal RC oscillator.

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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simpsonss
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Posted by simpsonss: Tue. May 5, 2009 - 04:00 AM
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hi glitch,

thanks. ok this is my fuse setting.
CKOPT =1
CKSEL3 =1
CKSEL2 =1
CKSEL1 =1

am i correct?

thank you.

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Gold Markclawson
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Posted by clawson: Tue. May 5, 2009 - 09:03 AM
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That looks like it should work. You may also want to make sure CKOPT=1, SUT1=1, SUT0=1 which (with CKSEL0) will select the very longest startup time allowing the crystal to settle into resonance.

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simpsonss
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Posted by simpsonss: Thu. May 7, 2009 - 07:15 AM
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hi all,
the programmer i built works so far but somehow for now it is not working anymore.will it be i accidentally set some of the fuse bit and lock some of the security bits?before that it works well and program can be run.first of all i had already double tripple check the circuit. and even built a new one.but it still seems not working.So i'm wondering will it be i set some of the fuse bit and lock the IC?

thank you.

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