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2 RF Configuration and Control Mechanism
2.1
Operation Status
The RF part of CMT2189C has four main operation statuses: SLEEP, XO-STARTUP, TUNE and TRANSMIT.
SLEEP
In this status, the whole module of RF is in a low power status, and the internal related circuits are closed, and
the consumption is only 20nA (only for the RF part).
XO-STARTUP
In the sleep status, the RF part will start up the oscillator when it is triggered by the RFDAT edge (rising edge).
TUNE
This status is that the frequency synthesizer tunes the oscillation frequency to the desired value.
TRANSMIT
After the frequency synthesizer tuned the frequency to the desired value, the transmitted data is input through
RFDAT to control the PA transmitting.In the transmitting process, if the time RFDAT holds a low level is longer
than t
STOP
setting time (T
STOP
is not unique, and can be selected. the specifics refer to RFPDK and the
following chapters), the RF part will automatically stop the transmitting and enter the SLEEP status.
Table 2-1.Status Switching Time
Parameter
Symbol
Min
Typ
Max
Unit
XTAL Startup Time [1]
tXTAL
400
us
Time to Tune to Desired Frequency
tTUNE
370
us
Hold Time After Rising Edge
tHOLD
10
ns
Time to Stop the Transmission[2]
tSTOP
2
90
ms
Notes:
This parameter mainly depends on the crystal itself. The range is from 2 ms to 9ms (step unit is 1ms, only
for FSK), and from 20ms to 90ms (step unit is 10ms).
2.2
Transmitting Control Timing
The RF transmitting of CMT2189C is mainly controlled by setting RFDAT (RFCLK holds the high level in the
process of transmitting), and the specific timing diagram is as follows:
