COMMUNICATION PROTOCOL

6

MC33592 Technical Data

MOTOROLA

Figure 5 : Complete message example

MESSAGE PROTOCOL

If the receiver is continuously Sleep/Run cycling, the ID word has to be recognized to stay in Run mode.

Consequently, the transmitted ID burst has to be long enough to include two consecutive receiver Run cycles.

If the Strobe oscillator is enabled (SOE=1), the circuit is in Sleep mode during SR

Therefore, the sleep/run cycle period is equal to (SR+1)

If SOE=0, these timings constraints must be respected by the external control applied on pin STROBE.

Figure 6 : Complete telegram with ID detection

Figure 7 : Complete telegram with tone detection

Figures 8 & 9 detail RF signals and the processing done by the receiver in several configuations.

Figure 8 : Telegrams with ID

Preamble

11001000

ID

Preamble

01

0

Header

1

1 0

Data

EOM

P+ID

RF signal

P+Header

Data

EOM

Run

Sleep

ID detected

Run

SR

P+ID

P+ID

P+ID

P+ID

P+ID

Sleep

P+ID =Preamble ID

P+Header

= Preamble Header

RF signal

Header

Data

EOM

Tone

Run

Sleep

ID detected

Run

SR

Sleep

Preamble ID

Preamble ID

Preamble ID

Header

Preamble

Data

EOM

Data

DME=1, HE=1

RF signal

SPI output

DME=1, HE=0

ID

Preamble ID

Data

EOM

RF signal

ID

ID

ID

ID

ID

ID

ID

ID

ID

ID

ID

ID

ID detected

ID detected

Freescale Semiconductor, Inc.

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