CCS / ADS1299：Test signal is incorrect

user5121970

Part Number: ADS1299

Tool/software: Code Composer Studio

I used the EVM to test the internally generated square wave of the ADS1299. At the same time, I connected the logic analyzer to the ADS1299. However, the data obtained from the logic analyzer is different from the data obtained by the EVM. What is wrong? To get the correct output on the instrument?

TI EVM

EXCEL (Channel 1)

Y ais：Voltages

logic analyzer

Full signal diagram

Fragment signal

EXCEL(Channel 1)

over 5 years ago

0 Alexander Smith over 5 years ago

TI__Guru 55342 points

Hi,

Can you describe what the difference is that you are seeing?

0 user5121970 over 5 years ago in reply to Alexander Smith

Intellectual 425 points

The data obtained from the logic analyzer, if only a part of the data is taken for drawing, it will become the following figure, which is different from the data obtained from the EVM

0 user5121970 over 5 years ago in reply to user5121970

Intellectual 425 points

Should the output from both the EVM and the logic analyzer be the same?

0 Alexander Smith over 5 years ago in reply to user5121970

TI__Guru 55342 points

Hi,

What you're reading for the logic analyzer is the 24bit representation of 1 measurement. Please see 9.5 Programming in the datasheet for more details.

The test signal from the EVM is a square wave, made of up many many measurements.

You have to convert this code back to a voltage in order to get a result similar to what you're seeing on the EVM. Please see the code to volts FAQ located here:https://e2e.ti.com/support/data-converters/f/73/p/772058/2855202

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CCS / ADS1299：Test signal is incorrect