SX1276 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX1276' PDF : 132 Pages View PDF
WIRELESS, SENSING & TIMING
SX1276/77/78/79
DATASHEET
The header is transmitted with maximum error correction code (4/8). It also has its own CRC to allow the receiver to
discard invalid headers.
Implicit Header Mode
In certain scenarios, where the payload, coding rate and CRC presence are fixed or known in advance, it may be
advantageous to reduce transmission time by invoking implicit header mode. In this mode the header is removed from the
packet. In this case the payload length, error coding rate and presence of the payload CRC must be manually configured
on both sides of the radio link.
Note With SF = 6 selected, implicit header mode is the only mode of operation possible.
Explicit Header Mode:
In Explicit Header Mode, the presence of the CRC at the end of the payload in selected only on the transmitter side through
the bit RxPayloadCrcOn in the register RegModemConfig1.
On the receiver side, the bit RxPayloadCrcOn in the register RegModemConfig1 is not used and once the payload has
been received, the user should check the bit CrcOnPayload in the register RegHopChannel. If the bit CrcOnPayload is at
‘1’, the user should then check the Irq Flag PayloadCrcError to make sure the CRC is valid.
If the bit CrcOnPayload is at ‘0’, it means there was no CRC on the payload and thus the IRQ Flag PayloadCrcError will not
be trigged even if the payload has errors.
Explicit Header
Value of the bit
RxPayloadCrcOn
Transmitter
0
0
1
1
Receiver
0
1
0
1
CRC Status
CRC is not checked
CRC is not checked
CRC is checked
CRC is checked
Implicit Header Mode;
In Implicit Header Mode, it is necessary to set the bit RxPayloadCrcOn in the register RegModemConfig1 on both sides
(TX and RX)
Implicit Header
Value of the bit
RxPayloadCrcOn
Transmitter
0
0
1
1
Receiver
0
1
0
1
CRC Status
CRC is not checked
CRC is always
wrong
CRC is not checked
CRC is checked
Rev. 4 - March 2015
©2015 Semtech Corporation
Page 30
www.semtech.com
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