CCS/PGA411-Q1: Automatic Offset Correction Timing Problems

user4661617

Part Number: PGA411-Q1
Other Parts Discussed in Thread: TMS320F28335,

Tool/software: Code Composer Studio

Hi~
I've read the link to this URL 'e2e.ti.com/.../2077069

I still have two questions.

(1) When I use the PGA411-Q1 communication with TMS320F28335 via SPI, How can I use SPI communication to know that the automatic offset calibration is running or not.
(2)On PGA411-Q1 EVM, according to the ORDCLK(ORD[13]) waveform acquired by the oscilloscope, see the figure below, automatic offset calibration procedure(△X) lasts 2.2ms.It is not between 200 μs and 400 μs.Can you help me to explain why?

over 9 years ago

0 Clancy Soehren over 9 years ago

TI__Mastermind 23810 points

Thank you for posting your question. We will be releasing an updated datasheet soon to fix the automatic offset calibration description. It does take about 2.3ms; however, the angle and velocity output continue to be available during this time. If you look at the AOUT pin (or read the angle through SPI), you should see that the angle output is correct during the calibration time.

Thanks,

-Clancy

0 user4661617 over 9 years ago in reply to Clancy Soehren

Prodigy 155 points

Hi Clancy,
Thank you very much.Another question, is the SPI register refresh frequency a fixed value?Can you tell me the frequency?

0 Clancy Soehren over 9 years ago in reply to user4661617

TI__Mastermind 23810 points

Can you clarify what you mean by "SPI register refresh frequency"? Are you talking about the continuous CRC check option of the PGA411?

Thanks,

-Clancy

0 user4661617 over 9 years ago in reply to Clancy Soehren

Prodigy 155 points

Dear Clancy,
I want to know the angle values (which are stored in DEV_STAT5 Register) refresh frequency.
Thanks.

0 Clancy Soehren over 9 years ago in reply to user4661617

TI__Mastermind 23810 points

The DEV_STAT5 register is refreshed on the rising edge of the NCS pin at the end of the SPI command to read the DEV_STAT5 register. The response on the SDO pin during the next frame will contain this data.

0 user4661617 over 9 years ago in reply to Clancy Soehren

Prodigy 155 points

Dear Clancy,
That solved my question.
Thank you very much.

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CCS/PGA411-Q1: Automatic Offset Correction Timing Problems