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AD7714 Output rate and DRDY

Question asked by Didro on Nov 16, 2010
Latest reply on Nov 16, 2010 by MMA

Hello,

 

I use AD7714 to create high-precision temperature sensor.

I've a trouble with understanding of basic principles of AD7714 work.

 

In datasheet I see, that Output rate = Fclkin (1MHz in my case) / 128 / code, where code = F0-F11 in decimal form. And DRDY tell me, when I could read data from AD7714.

 

I switch on power supply of my AD7714 and connect AD7714's DRDY pin to oscilloscope. By default (I see that in datasheet) F0-F11 = 0x140 in hex or 320 in decimal. So Output rate = 1 000 000 / 128 / 320 = 24,4 Hz. But, as I see on my oscilloscope, DRDY frequency = 73,4 Hz.

 

Why default output rate doesn't equal to DRDY frequency ?

 

Thank you,

p.s. I put your attention that I do not use any microcontrollers on my experiment with understanding DRDY freq. - all registers have default values.

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