Data Sheet

Page 50
RFM95/96/97/98(W)
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WIRELESS & SENSING PRELIMINARY DATASHEET
4.2.4. Operating Modes in FSK/OOK Mode
The RFM95/96/97/98(W) has several working modes, manually programmed in RegOpMode. Fully automated mode
selection, packet transmission and reception is also possible using the Top Level Sequencer described in Section 4.2.8.
Table 67 Basic Transceiver Modes
Mode Selected mode Symbol Enabled blocks
000 Sleep mode Sleep None
001 Standby mode Stdby Top regulator and crystal oscillator
010
Frequency synthesiser to Tx
frequency
FSTx Frequency synthesizer at Tx frequency (Frf)
011 Transmit mode Tx Frequency synthesizer and transmitter
100
Frequency synthesiser to Rx
frequency
FSRx Frequency synthesizer at frequency for reception (Frf-IF)
101 Receive mode Rx Frequency synthesizer and receiver
When switching from a mode to another the sub-blocks are woken up according to a pre-defined optimized sequence.
4.2.5. Startup Times
The startup time of the transmitter or the receiver is dependant upon which mode the transceiver was in at the beginning.
For a complete description, Figure 17 below shows a complete startup process, from the lower power mode “Sleep”.
Current
Drain
IDDR (Rx) or IDDT (Tx)
IDDFS
IDDSL
IDDST
Timeline
0 TS_OSC TS_OSC
+TS_FS
TS_OSC
+TS_FS
+TS_TR
TS_OSC
+TS_FS
+TS_RE
FSTx Transmit
Sleep
mode
Stdby
mode
FSRx Receive
Figure 17. Startup
Process
TS_OSC is the startup time of the crystal oscillator which depends on the electrical characteristics of the crystal. TS_FS is
the startup time of the PLL including systematic calibration of the VCO.
Typical values of TS_OSC and TS_FS are given in Section 2.3.