2. Data Protocol and Signal Timing
The remote sensor is sending a RF data telegram every 2s or when the button S2 is pressed with the
temperature data. The base station receiver is polling for this data telegram on RF channel 433.92MHz in
regular intervals of 5ms. The RF transmission and data protocol of the remote sensor and the base
station is using the following settings:
•Transmission order is MSB first for preamble and data section
•RF channel: 433.92MHz
•Data rate: 8kBit/s with FSK modulation and Manchester encoding
•Deviation: ±8kHz
Each data packet uses 2 bits before and after the data telegram to force a Manchester code violation,
which is detected by the receiver to separate the data packets and to restart the synchronization
procedure of the receiver.
2.1. Data Protocol for Remote Sensor Telegram
The remote sensor data protocol parameters are shown in Table 2-1. The Manchester encoding is using a
low-to-high transition for a '0' bit and a high-to-low transition for a '1' bit.
Table 2-1. Data Protocol
Protocol Item # of Data Bits Value Description
Preamble 55 ‘1’ Pre-burst for wake-up and synchronization
Start bit 1 ‘0’ Start bit to indicate data payload
Data payload
8
0x14 ID for no valid sensor data
0x19 ID for low battery voltage (VCC < 2.2V)
0x64 ID for temperature data (–55 to +125°C)
16 Signed integer Temperature value (0.1°C resolution)
8 Checksum Checksum of ID and data payload as 2th complement
Total 88 Data telegram with Ttx = 11ms at 8kBit/s
The acknowledge protocol send by the remote sensor has the following data:
Table 2-2. Acknowledge Protocol
Protocol Item # of Data Bits Value Description
Preamble 55 ‘1’ Pre-burst for wake-up and synchronization
Start bit 1 ‘0’ Start bit to indicate data payload
Data payload
8 0x60 ID for RSSI data
16 Integer RSSI value [0-255]
8 Checksum Checksum of ID and data payload as 2th complement
Total 88 Data telegram with Ttx = 11ms at 8kBit/s
Atmel User Guide for the Evaluation Kit ATA8510-EK1 [APPLICATION NOTE]
Atmel-9343D-ATAN0046_Application Note-09/2016
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