PGA970: How to configure PGA970EVM for Vout.?

Shashidhar Madhugiri

Part Number: PGA970
Other Parts Discussed in Thread: USB2ANY,

Hello,

Recently I have purchased PGA970EVM for my LVDT sensor.

I could able to generate sine waveform for required frequency.

I am using 5-wire connection of LVDT, ADC capture starts with 1.7 V and reaches maximum voltage of 2.9 V. May i know the why it starts at 1.7V?

I am unable to get any signals at Vout pin. Do i need to upload any code to configure PGA970EVM for DAC?(Please provide any reference manual)

I am using PGA970EVM with USB2ANY interface.

Your help is highly appreciable.

over 5 years ago

0 Scott Cummins over 5 years ago

TI__Mastermind 31655 points

Hello Shashidhar,

The voltage range could be due to some offset in your sensor output that is being amplified by the secondary input gains.

The VOUT output is not connected internally to the analog inputs without firmware running on the internal M0. The M0 is needed to read the demodulator outputs and do any correction/linearization needed and then provide an output code to the DAC that drives VOUT.

For firmware development to drive the output please refer to this post: https://e2e.ti.com/support/sensors/f/1023/t/802433

Regards,

0 Shashidhar Madhugiri over 5 years ago in reply to Scott Cummins

Prodigy 60 points

Dear Scott Cummins,

Thank you for your answer.

I have uploaded .hex file generated from PGA970 Generic-Firmware on FRAM (not DEVRAM) using USB2ANY. Does it configure the DAC for Vout?

Thank you

0 Scott Cummins over 5 years ago in reply to Shashidhar Madhugiri

TI__Mastermind 31655 points

Hello Shashidhar,

The example firmware contains shell functions as an example of the overall project structure, but the application specific software is not included. By default, the DAC will not be updated with values based on the demodulator results. This is something that the user must write.

Regards,

0 Shashidhar Madhugiri over 5 years ago in reply to Scott Cummins

Prodigy 60 points

Dear Scott,

Thank you for your reply.

I would really appreciate, if you can suggest a link to any reference/example code to configure DAC on PGA970..

I have generated hex file using the procedure as mentioned in the document "Quick guide to software" SLDU025, but still no output.

Thank you once again for your kind reply.

Regards,

Shashidhar M

0 Scott Cummins over 5 years ago in reply to Shashidhar Madhugiri

TI__Mastermind 31655 points

Hello Shashidhar,

We are currently unable to provide specific firmware development support outside of the available reference material. All of the available reference is listed in this post: https://e2e.ti.com/support/sensors/f/1023/t/802433

Setting the DAC is a matter of configuring the DAC output stage, which is described in the DAC output section of the datasheet, and then writing a value to the DAC_REG0_x registers. Processing the demodulator outputs and passing the result to the DAC is up to the user.

Regards,

0 Shashidhar Madhugiri over 5 years ago in reply to Scott Cummins

Prodigy 60 points

HI Scott,

Thank you for your answer.

Regards,

Shashidhar

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PGA970: How to configure PGA970EVM for Vout.?