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RF68

4. Application Modes of the RF68

Pins CTRL and DATA are used for both configuring the circuit and sending the data to be transmitted over the air. Two

different modes are associated to these pins, “Power&Go” and “Advanced” modes.

4.1. Transmitter Modes

Automatic Mode operation is described in Figure 2. Here we see that a rising edge on the DATA pin activates the

transmitter start-up process. DATA must be held high for the start-up time (TS_TR) of the RF68. During this time the

RF68 undergoes an optimized, self-calibrating trajectory from Sleep mode to Transmit mode. Once this time has elapsed,

the RF68 is ready to transmit. Any logical signal subsequently applied to the DATA pin is then transmitted.

Figure 2. ‘Power & Go’ Mode: Transmitter Timing Operation

The transition back to Sleep mode is managed automatically. The RF68 waits for TOFFT (2 or 20 ms) of inactivity on

DATA before returning to Sleep mode.

In Forced Transmit Mode the circuit can be forced to wake up and go to TX mode by sending an APPLICATION

instruction through the TWI interface, and setting the Mode bit DA(15) to ‘1’. Once in Transmit the circuit will transmit over

the air the data stream presented on the DATA pin. The circuit will stay in transmit mode until a new APPLICATION

instruction is sent with DA(15) to ‘0’.

Figure 3. Forced Transmit Mode Description