Warmup times

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Warmup times

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Contributor II

How long does TxWarmup, RxWarmup, TxPartialWarmup and RxPartialWarmdown take on the MKW2x?

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Senior Contributor I

Dear Jssn,

TX and RX warmup times are both set to 144 uS. There are no further details about timing diagrams available. Sorry for the inconvenience.

Regards,

AngelC

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Contributor II

What is the difference between TxWarmup and TxPartialWarmup?

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Senior Contributor I

Dear Jssn,

When transitioning from RX to TX with no delay, radio does not need to fully warm down and back up, simply warm down to some point where the only circuits turned on are those needed for TX (some analog regulators, for instance). So the radio partially warm down and partial up.

Regards,

AngelC

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Contributor II

Hi AngelC,

How long does it take for the following transmit sequence until the preamble starts?

CCA mode 1, Slotted=0

<RX Warmup>,<CCA1>,<RxPartialWarmdown>,<TxPartialWarmup>

144us,128us,??,??,

Does <RxPartialWarmdown>,<TxPartialWarmup> take 144us in total?

Additionally, when using T2CMP to initiate the sequence, does the sequence begin at the moment Modem_EVENT_TIMER equals Modem_T2CMP or the moment it equals Modem_T2CMP  and increments (similar to functioning of the Kinetis LPTMR compare)?

Thanks

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Contributor III

Not every step is completely documented, even internally. For instance, only TXPartialWarmDown is documented but timing of RXPartialWarmDown is not, assuming it is the same, see the numbers below, but it may be shorter, or it could be longer.

Reviewing the data we have, this is what I come up with:

RXWarmup = 144us

CCA1 = 128us

RXPartialWarmDown = 10us ? (may be less time)

TXPartialWarmUp = 114us (144us-30us)

So 144+128+10+114 = 396us (with some uncertainty)

Hope this helps

Bill Poole

Freescale Semiconductor

Connectivity and IoT Solutions, Microcontrollers

Applications Engineering

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Contributor II

Hi Bill,

Is it possible to get a more definitive answer from your hardware development team?

To summarize, I would like to know with more certainty how long it takes from the start of triggering SequenceTransmit until the start of transmission in the case where Clear Channel Assessment is performed and also in the case without CCA.

Thank you

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Contributor II

Will there be an update to the MKW2x reference manual any time soon that documents the radio TX and RX timing?

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NXP Employee
NXP Employee

Hello Jssn,

The partial warm up timing depends on the scenario (slotted, non-slotted, etc), so there's no single answer to your question.

Can you provide your specific settings?

I'm not aware of the addition of the TX/RX timings in the next RM update, but I'll double check.

Juan Carlos

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