RFM22 Datasheet, PDF (16/150 Pages) –

RFM22
3.2. Operating Mode Control
There are four primary states in the RFM22 radio state machine: SHUTDOWN, IDLE, TX, 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 TX
and RX state may be reached automatically from any of the IDLE states by setting the txon/rxon bits in "Register
07h. Operating Mode and Function Control 1". Table 11 shows each of the operating modes with the time required
to reach either RX or TX 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
TX State
1
RX State
1
Figure 6. State Machine Diagram
Table 11. Operating Modes
Response Time to
Current in State
pll
wt LBD or TS
TX
RX
/Mode [μA]
X
X
X
16.21 ms 16.21 ms
10 nA
0
0
0
1
0
X
0
X
1
X
1
X
1
X
0
1.21 ms
1.21 ms
400 nA
0
800 nA
1
1 μA
X
210 μs
210 μs
600 μA
X
200 μs
200 μs
9.5 mA
80 mA @ +17dBm,
X
NA
200 μs
27 mA @ +8 dBm
X
200 μs
NA
18.5 mA
16
Tel: [phone] Fax: [phone] E-mail: [e-mail] http://www.hoperf.com