ADS7957-Q1: Question about reset and initialization of ADS7957-Q1

Takumi Suzuki1

Mastermind 8420 points

Part Number: ADS7957-Q1
Other Parts Discussed in Thread: ADS7957

Hi,

I would like to ask you some questions related reset of ADS7957-Q1 as below.

Q1) Reset

I suppose there is no "reset" pin with ADS7957.

Could you tell me how to reset this device?

Only power-up or register control, correct?

Q2) Power-On (Power-Up) reset

About "Power-Up" reset, how should we know the timing that the device is on reset and initialized?

Need to check each 3 power (Analog, Digital, Reference) if they reach "Min" level?

Q3) Power-Up Sequence

There is a "Power-Up Sequence" on the datasheet, figure 49, page24.

Should we do all this sequence after power-up?

I think that we should do the register setting we need to change from initialized value.

Is my understanding correct?

Thank you and Best Regards,

over 7 years ago

0 Abhijeet Godbole over 7 years ago

TI__Expert 5485 points

Hi Takumi San

Please see my response below

1) Yes. device can be reseted through register control or power up

2) Yes .you should monitor all the rails and wait until they reach min value. also at no time your ADC input should be greater than supply rail (VA+)

3) For user intiated reset you need to write 0x4200 to device. Please refer to table 11 of datasheet for more information

Thanks & Regards

Abhijeet

0 Takumi Suzuki1 over 7 years ago in reply to Abhijeet Godbole

Mastermind 8420 points

Hi Abhijeet-san,

Thank you so much for your reply.

Let me confirm Q3 again if my understanding is correct as below.

If we plan to use this device on initial setting (after power-up), we need not to program auto-1 and auto-2 register.

Is my understanding correct?

Thank you for your support!

0 Takumi Suzuki1 over 7 years ago in reply to Takumi Suzuki1

Mastermind 8420 points

Abhijeet-san,

Sorry ask you one more question, please.
I think that we can stop SCLK between frames, correct?
Or SCLK has to run always? (We never stop SCLK running??)

Thanks for your support.

0 Abhijeet Godbole over 7 years ago in reply to Takumi Suzuki1

TI__Expert 5485 points

Hi Takumi San

After power up device default register settings will be as per table 1column 2(Reset state). If your expected device settings are different than what is given in this table then you need to write it evry time after power up. In what mode are you operating this device

Thanks & Regards

Abhijeet

0 Abhijeet Godbole over 7 years ago in reply to Takumi Suzuki1

TI__Expert 5485 points

Hi Takumi San

Free running clock is not required for data capture. You can stop SCLK after 16th Clk as shown in timing diagram

Regards

Abhijeet

0 Takumi Suzuki1 over 7 years ago in reply to Abhijeet Godbole

Mastermind 8420 points

Hi Abhijeet-san,

Thank you very much for your reply.

I understood.

Regards,

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ADS7957-Q1: Question about reset and initialization of ADS7957-Q1