FDC2214: Continuously sampling and reading

Yanbing Yu

Part Number: FDC2214

Setting up FDC2214 to continuously sampling on all 4 channels, and reading the measurements on interrupts. We'd like to understand how the reading of measurement is protected from the on-going new measuring process? Are the data registers, such as "DATA_CHx" & "DATA_LSB_CHx", double buffered and isolated from the measuring process?

over 2 years ago

0 John Miller - Sensing over 2 years ago

TI__Mastermind 40295 points

Yanbing,

I will check on your question and post a reply tomorrow.

Regards,

John

0 Justin Beigel over 2 years ago in reply to John Miller - Sensing

TI__Mastermind 18545 points

Hello Yanbing,

The FDC2214 requires that you read the MSB data register before reading the LSB data register.

When you read the MSB data register, the LSB data register is loaded with the corresponding data. This prevents the LSB portion of the data from being overwritten by the next sample once you start reading the data. However, the MSB data registers will update with each sample measurement cycle.

Best Regards,
Justin Beigel

0 Yanbing Yu over 2 years ago in reply to Justin Beigel

Prodigy 20 points

Justin,
Thanks for your reply. So there is a risk of reading incorrect MSB, because it was overwritten by new measurement while reading. Right?
How to prevent this from happening? Is there a time limit that reading (via I2C) shall be done?

Thanks!

0 Justin Beigel over 2 years ago in reply to Yanbing Yu

TI__Mastermind 18545 points

Hello,

The register won't change while you are actively reading it. If you do not read them data every sample interval then samples will be lost as the data is overwritten after the next sample interval completes.

Best Regards,

Justin Beigel

0 Yanbing Yu over 2 years ago in reply to Justin Beigel

Prodigy 20 points

Justin, thanks for your replies! Great help!

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FDC2214: Continuously sampling and reading