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.
How long does it take for the following transmit sequence until the preamble starts?
CCA mode 1, Slotted=0
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)?
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
Connectivity and IoT Solutions, Microcontrollers
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.
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.