RFM70 V1.0
VDD>=1.9
V
Power Down
PWR_UP=1
PWR_UP=0
Standby-I
CE=1
CE=0
CE=0
ACK packet transmitted
RX
TX
Packet received
EN_AA=1
NO_ACK=0
Figure 4 PRX (PRIM_RX=1) state control diagram
4.2 Power Down Mode
4.4 Standby-II Mode
In power down mode RFM70 is in sleep
mode with minimal current consumption. SPI
interface is still active in this mode, and all
register values are available by SPI. Power
down mode is entered by setting the PWR_UP
bit in the CONFIG register to low.
In standby-II mode more clock buffers are
active than in standby-I mode and much more
current is used. Standby-II occurs when CE is
held high on a PTX device with empty TX
FIFO. If a new packet is uploaded to the TX
FIFO in this mode, the device will
automatically enter TX mode and the packet is
transmitted.
4.3 Standby-I Mode
4.5 TX Mode
By setting the PWR_UP bit in the CONFIG
register to 1 and de-asserting CE to 0, the
device enters standby-I mode. Standby-I mode
is used to minimize average current
consumption while maintaining short start-up
time. In this mode, part of the crystal oscillator
is active. This is also the mode which the
RFM70 returns to from TX or RX mode when
CE is set low.
PTX device (PRIM_RX=0)
The TX mode is an active mode where the
PTX device transmits a packet. To enter this
mode from power down mode, the PTX device
must have the PWR_UP bit set high,
PRIM_RX bit set low, a payload in the TX
FIFO, and a high pulse on the CE for more
than 10µs.
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