RFM31 Datasheet, PDF (14/137 Pages) –

RFM31
3.2. Operating Mode Control
There are three primary states in the RMF31 radio state machine: SHUTDOWN, IDLE, and RX (see Figure 6). The
SHUTDOWN state completely shuts down the radio to minimize current consumption. There are five different
configurations/options for the IDLE state which can be selected to optimize the module to the applications needs.
"Register 07h. Operating Mode and Function Control 1" controls which operating mode/state is selected. The RX
state may be reached automatically from any of the IDLE states by setting the rxon bit in "Register 07h. Operating
Mode and Function Control 1". Table 10 shows each of the operating modes with the time required to reach RX
mode as well as the current consumption of each mode.
The output of the LPLDO is internally connected in parallel to the output of the main digital regulator (and is
available externally at the VR_DIG pin); this common digital supply voltage is connected to all digital circuit blocks,
including the digital modem, crystal oscillator, and SPI and register space. The LPLDO has extremely low
quiescent current consumption but limited current supply capability; it is used only in the IDLE-STANDBY and
IDLE-SLEEP modes.
State/Mode
xtal
Shut Down State
X
Idle States:
Standby Mode
0
Sleep Mode
0
Sensor Mode
0
Ready Mode
1
Tune Mode
1
RX State
1
Figure 6. State Machine Diagram
Table 10. Operating Modes
pll
wt LBD or TS Response Time to RX
X
X
X
16.21 ms
Current in State
/Mode [μA]
10 nA
0
0
0
0
1
0
0
X
1
0
X
X
1
X
X
1
X
X
1.21 ms
210 μs
200 μs
NA
400 nA
800 nA
1 μA
600 μA
9.5 mA
18.5 mA
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