MC68HC908RF2 Datasheet, PDF (227/254 Pages) Motorola, Inc – HCMOS Microcontroller Unit

PLL Tuned UHF Transmitter Module
State Machine
State 1
The circuit is in standby mode and draws only a leakage current from
the power supply.
State 2
In this state, turÃPLL is enabled but out of the lock-in range. Therefore
the RF output stage is switched off preventing any data transmission.
D In h‡hÃpy‚pxÃv†Ãh‰hvyhiyrÃvÃ96U68GFà normal operation, this
state is transitional.
State 3
In this state, the PLL is within the lock-in range.
If t < t_{PLL_Lock_In}, then the PLL can still be in acquisition mode.
If t ≥ t_{PLL_Lock_In}, then the PLL is locked.
The circuit is ready to transmit in band and is waiting for the first data
(see Figure 16-3).
State 4
A rising edge on pin DATA starts the transmission. Data entered on
pin DATA are output on pin RFOUT. The modulation is the one
selected through the level applied on pin MODE.
State 5
An out-of-lock condition has been detected. The RF output stage is
switched off preventing any data transmission. Dh‡hÃpy‚pxÃv†Ãh‰hvyhiyrÃ
‚ÃƒvÃ96U68GF
State 6
When the supply voltage falls below the shutdown voltage threshold
(V_SDWN) the whole circuit is switched off. Applying a low level on pin
ENABLE is the only condition to get out of this state.
Figure 16-3 shows the waveforms of the main signals for a typical
application cycle
MC68HC908RF2 — Rev. 1
MOTOROLA
PLL Tuned UHF Transmitter Module
Advance Information
227