Any way to get Flex Timer clock frequency, K20dx256zvll10

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Any way to get Flex Timer clock frequency, K20dx256zvll10

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Cdn_aye
Senior Contributor I

Hi

We are using a 16Mhz crystal on a K20dx256 and I think it is upscaled to 96Mhz. We use the system clock with the PIT timer to measure a signal coming in on FTM0. The counts in the PIT are used to drive an output slightly scaled from the incoming signal. All this works, now I need to know the exact period of the PIT clock so we can do another calculation. I believe the clock is set to divide the system clock down by 8 but when I generate a signal on an output pin that I toggle when the PIT is loaded with 1000 counts I get 24kz. As far as I can see the numbers don't work. I am wondering if the bus clock isn't really running at 96Mhz/2 = 48 Mhz.

Is there any way to determine the period of the PIT clock exactly? I was hoping MQX had such a mechanism or if anyone could suggest a way to determine the PIT clock exactly.

Thanks for any advice,

Robert

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DavidS
NXP Employee
NXP Employee

Hi Robert,

The K20DX256 would clock the PIT from the OUTDIV2/Bus Clock which typically is the core frequency divided by 2 (i.e. 96MHz/2=48MHz).

Regards,

David

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750件の閲覧回数
DavidS
NXP Employee
NXP Employee

Hi Robert,

The K20DX256 would clock the PIT from the OUTDIV2/Bus Clock which typically is the core frequency divided by 2 (i.e. 96MHz/2=48MHz).

Regards,

David

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Cdn_aye
Senior Contributor I

Hi David

Thank you, I can see that it is correction  now. I was overlooking the divide by 2 for the clock to bus.

Regards

David

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