ADS1220 internal temperature sensor

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#1
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Hello, I'm trying to read internal temperature sensor data of ADS1220.

But I don't understand result: under normal conditions (temp ~25 deg C) device reads 0x000FD1B6

If I heat it with my finger it reads something around 0x0010AC5C

 

Datasheet says:

Temperature data are represented as a 14-bit result that is left-justified within the 24-
bit conversion result. Data are output starting with the most significant byte (MSB). When reading the three data
bytes, the first 14 bits are used to indicate the temperature measurement result. One 14-bit LSB equals
0.03125°C.

 

Whole quote from ADS1220's datasheet:

 

So if I shift 8 bits from 0x0010AC5C I will get 0x0010AC, which is more than 128 degrees.

 

External temperature reads OK.

Alexander

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Gordon01 wrote:
I don't understand result: under normal conditions (temp ~25 deg C) device reads 0x000FD1B6

 

I don't understand it either, your value is too big for 25C, so show us the raw data read from the device and how you got your value of 0x000FD1B6 from it.

The device data is left justified, but your data is right justified, show how you did that?

 

Jim

 

 

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Do you have the correct SPI mode selected?

 

From the datasheet:

SPI-Compatible Interface Mode 1)

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly