Datasheet
Table Of Contents
- 1. General Description
- 2. Electrical Characteristics
- 3. SX1272/73 Features
- 4. SX1272/73 Digital Electronics
- 4.1. The LoRaTM Modem
- 4.2. FSK/OOK Modem
- 4.2.1. Bit Rate Setting
- 4.2.2. FSK/OOK Transmission
- 4.2.3. FSK/OOK Reception
- 4.2.4. Operating Modes in FSK/OOK Mode
- 4.2.5. General Overview
- 4.2.6. Startup Times
- 4.2.7. Receiver Startup Options
- 4.2.8. Receiver Restart Methods
- 4.2.9. Top Level Sequencer
- 4.2.10. Data Processing in FSK/OOK Mode
- 4.2.11. FIFO
- 4.2.12. Digital IO Pins Mapping
- 4.2.13. Continuous Mode
- 4.2.14. Packet Mode
- 4.2.15. io-homecontrol® Compatibility Mode
- 4.3. SPI Interface
- 5. SX1272/73 Analog & RF Frontend Electronics
- 6. Description of the Registers
- 7. Application Information
- 8. Packaging Information
- 9. Revision History
www.semtech.comPage 116
SX1272/73
WIRELESS, SENSING & TIMING DATASHEET
Rev. 2 - July 2014
©2014 Semtech Corporation
7.3.1.1. Timing Diagram
When no signal is received, the circuit wakes every Timer1 + Timer2 and switches to Receive mode for a time defined by
Timer2, as shown on the following diagram. If no Preamble is detected, it then switches back to Idle mode, i.e. Sleep mode
with RC oscillator on.
Figure 49. Listen Mode with No Preamble Received
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.
Figure 50. Listen Mode with Preamble Received
No received signal
Receive ReceiveIdle ( Sleep + RC ) Idle
Timer2
Timer1
Timer2
Timer1Timer1
Timer2
Received signal
Preamble ( As long as T1 + 2 * T2 )
Sync
Word
Payload Crc
ReceiveIdle ( Sleep + RC )
Timer1
Preamble
Detect
Timer2