Data Buffer; Rssi Functionality; Table 8-26: Rssi Information Origin And Meaning - Semtech LR1121 User Manual

8.8 Data Buffer

The LR1121 is equipped with two 255 byte RAM data buffers which are accessible in all modes except sleep mode. One
buffer stores the received payload data, while the other contains the payload data to be transmitted.
The LR1121 automatically controls the data pointers, which means that no base address handling by the user is necessary.
•
Data Buffer in Receive Mode:
The received payload data are stored in the RX buffer:

They can be read back using command ReadBuffer8(...) (see

GetRxbufferStatus(...) reads the pointer to the first byte of the last packet received and the packet

length (see 7.2.11
ClearRxBuffer(...) clears all the data in the LR1121 RX buffer (see

•
Data Buffer in Transmit Mode:
The payload data to be transmitted shall be written the Tx Buffer using command WriteBuffer8(...) (see

WriteBuffer8)

8.9 RSSI Functionality

The RSSI information of the LR1121 is available either in the radio chain, or after demodulation at the end of the reception
stage. A summary of the RSSI information and their meaning is summarized in table
Meaning below:

Table 8-26: RSSI Information Origin and Meaning

Command
GetRssiInst(...)
GetPacketStatus(...)
Refer to each command description for implementation details on the various RSSI fields.
LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
GetRxBufferStatus).
Name
Modem
RssiInst
All
RssiSync
(G)FSK
RssiAvg
RssiPkt
LoRa®
SignalRssiPkt
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3.7.5
3.7.6
Instantaneous RSSI
Instantaneous RSSI value latched in the (G)FSK demodulator, upon
detection of sync address
Average RSSI value over the whole payload of the received packet,
determined in the (G)FSK demodulator.
Measurement of the mean energy at the input of the modem over the
last packet received.
Estimation of the mean energy of the LoRa signal over the last packet
received. Equivalent to RssiPkt - environment noise
ReadBuffer8)
ClearRxBuffer)
Table 8-26: RSSI Information Origin and
Description
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3.7.4
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