TMS320F28388D: AdcSetMode() can be called after power up an ADC block ?

Hidehiko Kaya

Intellectual 700 points

Part Number: TMS320F28388D
Other Parts Discussed in Thread: C2000WARE

Hi experts,

Our ADC initialized code calls AdcSetMode() after initialization of ADC block.

And we change 12-bit mode and 16-bit mode dynamically on an ADC balock.

In TRM (spruii0c), the initialization is the following sequence.

----------------------------------------------------

20.10 Power-Up Sequence
Upon device power-up or system level reset, the ADC will be powered down and disabled. When powering up
the ADC, use the following sequence:
1. Set the bit to enable the desired ADC clock in the PCLKCR13 register.
2. Set the desired ADC clock divider in the PRESCALE field of ADCCTL2.
3. Power up the ADC by setting the ADCPWDNZ bit in ADCCTL1.
4. Allow a delay before sampling. See the data manual for the necessary time.

----------------------------------------------------

In C2000Ware examples, AdcSetMode() is called between step2 and step3 in ConfigureADC().

It is called before power up ADC blocks.

Does AdcSetMode() need power down to call ?

Best regards,

Hidehiko

over 4 years ago

0 Vasudha Bhadoria over 4 years ago

TI__Genius 10845 points

Hi,

I think the idea here is to configure the ADC and then power it up since it is a onetime configuration. Are you trying to change the ADC mode in run time?

Thanks

Vasudha

0 Hidehiko Kaya over 4 years ago in reply to Vasudha Bhadoria

Intellectual 700 points

Hi, Vasudha

>Are you trying to change the ADC mode in run time?

Yes, we need to change.

Best regards,

Hidehiko

0 Vasudha Bhadoria over 4 years ago in reply to Hidehiko Kaya

TI__Genius 10845 points

Hidehiko Kaya said:
Yes, we need to change

The ADC_setMode() API can be used to configure the mode in runtime but there are few constraints on changing the resolution in runtime such as there should be no active conversion going on. PFB the description from TRM on this:

The resolution can be changed at any time when the ADC is idle (no active or pending SOCs). No wait
time is necessary after changing the resolution before conversions can be initiated. If SOCs are active or
pending when the resolution is changed, those SOCs may produce incorrect conversion results.

Thanks
Vasudha

0 Hidehiko Kaya over 4 years ago in reply to Vasudha Bhadoria

Intellectual 700 points

Hi, Vasudha

Thank you for your information.

AdcSetMode() can be called to change a resolution(12 <-> 16) when ADC is idle.

In other words, an application program can get correct ADC result after a few milliseconds (= enough delay).

Is my understanding right ?

Best regards,

Hidehiko

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TMS320F28388D: AdcSetMode() can be called after power up an ADC block ?