RFM119W/RFM119SW

Rev 1.0 | Page 14 /19

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5.6.1 Tx Enabled by DATA Pin Rising Edge

As shown in the figure below, once the RFM119W/RFM119SW detects a rising edge on the DATA pin, it goes into the XO-

input data after

STATE

SLEEP

XO-STARTUP TUNE

TRANSMIT

SLEEP

Rising Edge

DATA pin

0

1

Don’t Care

Valid Transmitted Data

0

PA out

RF Signals

Figure 16. Transmission Enabled by DATA Pin Rising Edge

5.6.2 Tx Enabled by DATA Pin Falling Edge

As shown in the figure below, once the RFM119W/RFM119SW detects a falling edge on the DATA pin, it goes into XO-

STARTUP state and the XO starts to work. During the XO-STARTUP state, the DATA pin needs to be pulled low. After the XO

is settled, the RFM119W/RFM119SW goes to the TUNE state. The logic state of the DATA pin is “Don't Care” during the TUNE

state. In the TRANSMIT state, PA sends out the input data after they are modulated. The user has to pull the DATA pin low for

transmission. Before starting the next transmit cycle, the user has to pull the DATA pin back to high.

STATE

SLEEP

XO-STARTUP TUNE

TRANSMIT

SLEEP

Falling Edge

DATA pin

1

0

Don’t Care

Valid Transmitted Data

0

1

PA out

RF Signals

Figure 17. Transmission Enabled by DATA Pin Falling Edge

5.6.3 Two-wire Interface

For power-saving and reliable transmission purposes, the RFM119W/RFM119SW is recommended to communicate with

the host MCU over a two-wire interface (TWI): DATA and CLK. The TWI is designed to operate at a maximum of 1 MHz.

The timing requirement and data transmission control through the TWI are shown in this section.