SX1232
WIRELESS & SENSING
DATASHEET
If a Preamble signal is detected, the Sequencer is switched off. The PreambleDetect signal can be mapped to DIO4, in
order to request the user's attention. The user can then take appropriate action.
Received signal
Sync
Word
Preamble ( As long as T1 + 2 * T2 )
Idle ( Sleep + RC )
Payload
Crc
Receive
Timer2
Timer2
Timer1
Preamble
Detect
Figure 45. Listen Mode with Preamble Received
7.4.1.2. Sequencer Configuration
The following graph shows Listen mode - Wake on PreambleDetect state machine:
State Machine
Sequencer Off
&
Initial mode = Sleep or Standby
IdleMode = 1 : Sleep
Start bit set
LowPowerSelection = 1
LowPower
Start
Idle
Selection
FromStart = 00
On T1
FromIdle = 1
On PreambleDetect
FromReceive = 110
On T2
Receive
Sequencer Off
Figure 46. Wake On PreambleDetect State Machine
This example configuration is achieved as follows:
Table 33 Listen Mode with PreambleDetect Condition Settings
Variable
Effect
IdleMode
1 : Sleep mode
FromStart
LowPowerSelection
00 : To LowPowerSelection
1 : To Idle state
FromIdle
FromReceive
1 : To Receive state on T1 interrupt
110 : To Sequencer Off on PreambleDetect interrupt
Rev 3 - August 2012
Page 86
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