RFM219SW Datasheet, PDF (19/35 Pages) List of Unclassifed Manufacturers – Wireless Alarm and Security Systems

RFM219SW
5.7 Operation States, Timing and Power
5.7.1 Power-Up Sequence
The chip operation starts from a valid power-on reset. It usually takes about 0.5 ms for the valid power-on reset to release. Once
the POR is released the crystal oscillator start oscillating. The time taken for the crystal oscillator to get stable is fixed at 2.5 ms in
the first power-up. After the crystal gets stable, it takes about 6.5 ms for the chip to perform the internal blocks calibrations. The
calibrations are only performed once at the beginning of one power-on cycle.
VDD
POR
Time
POR Release
<= 0.5 ms
XTAL Stablize
= 2.5 ms
Blocks Calibrations
<= 6.5 ms
Enters the SLEEP State
Ready to Work
Figure 16. Power-Up Sequence Timing
The chip enters the SLEEP mode as soon as the calibrations are done. From this point on, the MCU can then actively switch the
chip into different operating states by writing the register bits OP_SWITCH<4:0>.
5.7.2 Operating States
There are in all 6 operating states: PUP, SLEEP, STBY, TUNE, RX and EEPROM, as shown in the below table.
Table 12. RFM219SW Operation States
State
Command
PUP
SLEEP
soft_reset
go_sleep
STBY
go_stby
TUNE
go_tune
RX
go_rx
EEPROM go_eeprom
Active Blocks
POR, XTAL
SPI, POR
SPI, POR, XTAL, FIFO
SPI, POR, XTAL, PLL, FIFO
All
SPI, POR, XTAL
Optional Blocks
None
LFOSC, Sleep Timer
CLKO
CLKO
CLKO, RX Timer
CLKO
The 6 commands used by the MCU to switch the states are simply register-writing operation. Please see OP_CTRL and
SOFTRST register description for the details. The MCU can arbitrarily switch the states, as long as it complies with the switching
time requirement and rules. For example, the MCU can directly switch the chip from SLEEP state to RX state, while it has to wait
for the time of “Xtal Stabilizing Time + 300 us + 20 us” before taking any further actions in the RX state. While switching the states
backward, the time cost is negligible. Switching to the EEPROM state is only allowed in the SLEEP state. The soft reset will pull
the device back to the PUP state and re-perform the blocks calibrations.
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