Temperature Measurement ATtiny25

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san_juan_dad
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Posted by san_juan_dad: Fri. Jun 22, 2007 - 10:58 PM
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I’m struggling with temperature measurements on the ATtiny25. Hopefully someone else has actually used one to measure temperature and can help me get on the right path.

When I measure the device at room temp the numbers returned are in the range of 0x130. The data sheet says room temp should be 290 LSB, which I interpret to be 0x290. This might be my problem, 130 hex is about 300 base 10. So, that is close to the 290 in the datasheet.

Has anyone else look at this issue? And what conclusions have you come to?

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AVR Microcontrollers, megaAVR and tinyAVR, ATtiny25
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Bronze Marktheusch
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Posted by theusch: Fri. Jun 22, 2007 - 11:07 PM
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290 LSB would be 290 of 1023 decimal.

Lee

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Nuno
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Posted by Nuno: Sat. Jun 23, 2007 - 07:07 AM
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And "room temperature" is kind of variable.

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nanovate
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Posted by nanovate: Sat. Jun 23, 2007 - 08:18 AM
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Quote:

When I measure the device at room temp the numbers returned are in the range of 0x130. The data sheet says room temp should be 290 LSB, which I interpret to be 0x290. This might be my problem, 130 hex is about 300 base 10. So, that is close to the 290 in the datasheet.

I have used the temp sensor and those numbers are not out of the range for "room temp". The sensor is +/-10C after offset calibration. The internal voltage reference can also vary slightly from 1.1V which affects the resultant output code.

John

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