What is the bus clock frequency range for ADC on Kinetis K12 (MK12DN512)

[DeepakKukreja]

Hi,

On the MK12DN512VLK5 Kinetis K12 part, what is the clock frequency range for the ADC. The reference manual mentions in couple of places that the ADC clock frequency should be in the specified range but I could not find the actual frequency specification.

#kinetis_12‌, #adc clock frequency‌

[kerryzhou · Accepted solution]

Hi Deepak Kukreja,

  Which ADC clock source you are using now?

If you are using the ADACK, it is in the datasheet:

Best Regards,

Kerry

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[DeepakKukreja]

Hi kerryzhou,

Thanks for sharing the relevant portions from the Reference Manual.

From the snapshots of the reference manual, does it imply that only the ADACK needs to meet the specifications, and there is no such restrictions in case bus clock is used as the input clock?

I am planning on using the bus clock, and will be trying with the below options:

Can you please validate my calculations below:

OPTION 1: Bus clock (48 MHz) with no divider, fastest conversion

ADCx_CFG1[ADICLK] set to 0(dec). Input clock set to bus clock

ADCx_CFG1[ADIV]   set to 0(dec). Divide ratio is 1

I assume ADCK gets set to 48 MHz

OPTION 2: Bus clock(48 MHz)/2 with max. divider, slowest conversion

ADCx_CFG1[ADICLK] set to 1(dec). Input clock set to bus clock/2

ADCx_CFG1[ADIV]   set to 3(dec). Divide ratio is set to 8

I assume ADCK gets set to 3 MHz

I have another query regarding the conversion time calculation, but I will create a separate query for that

Thanks

[kerryzhou]

Hi Deepak Kukreja ,

  Other clock, you need to meet the conversion clock requirement:

Any new questions, welcome to create the new question post.

Best Regards,

Kerry

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