AM2431: PADCONF DRV_STR bits configuration

Koichiro Tashiro

Part Number: AM2431

Hi,

I have a question from my customer. Please answer below.
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I understand that there are 3 drive-strengh levels(fast/normal/slow).
I obeserved waveforms with varying DRV_STR value in 00b, 01b, 10b, 11b. As you can see in below excel sheet, with only DRV_STR=10b condition, the waveforms has higher slew rate(fast condition?), with DRV_STR=00b, 01b and 11b condition, the wavefoms has lower slew rate(slow? normal? condition?).
Only 2 levels of drive strength are available?

DRV_STR(No133).xlsx

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Thanks and regards,
Koichiro Tashiro

over 2 years ago

0 Sri Vidya Gunturi over 2 years ago

TI__Expert 7586 points

Could you please provide us more information?

How are you configuring the drive strength? And what is the requirement?

Regards

Sri Vidya

0 Koichiro Tashiro over 2 years ago in reply to Sri Vidya Gunturi

TI__Mastermind 22935 points

Hi Sri,

Sri Vidya Gunturi said:
How are you configuring the drive strength?

As you can see in the excel sheet, the customer just compare slew rate on the signal.

Sri Vidya Gunturi said:
And what is the requirement?

There is no clear requirement. The customer just wants to know if three levels of drive strength are available or not.
I think you can answer it without knowing customer's usecase, etc.

Thanks and regards,
Koichiro Tashiro

0 Sri Vidya Gunturi over 2 years ago in reply to Koichiro Tashiro

TI__Expert 7586 points

Hi Koichiro Tashiro

Got it. We will get back to you soon on this.

Regards

Sri Vidya

+1 Fleenor over 2 years ago in reply to Koichiro Tashiro

TI__Mastermind 23003 points

Hey Koichrio,

The drive strength bits should be left at their default values after reset. The default settings are used during timing analysis and therefore this is the only configuration option that has been validated and guaranteed by design. Recommendation is not to change these bits from default values. There are many factors that influence the true drive strength after the device has been integrated into a given system. It is often external components/conditions/requirements that become the bottleneck/ceiling/floor for the final slew rate seen in any given hardware implementation.

Best Regards,

Zackary Fleenor

0 Koichiro Tashiro over 2 years ago in reply to Fleenor

TI__Mastermind 22935 points

Hi Zackary,

I understood the default settings are recommended.
But could you confirm AM2431 has three drive strength configurations?

Thanks and regards,
Koichiro Tashiro

+1 Fleenor over 2 years ago in reply to Koichiro Tashiro

TI__Mastermind 23003 points

No, this is not a recommendation, it is a requirement. Only the single default drive strength configuration is a valid option, hence there is only one drive strength configuration.

Best Regards,

Zackary Fleenor

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AM2431: PADCONF DRV_STR bits configuration