RFM22 Datasheet, PDF (106/150 Pages) –

RFM22
Register 34h. Preamble Length
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
prealen[7:0]
Type
R/w
Reset value = 00001000
Bit
7：0
Name
prealen[7:0]
Function
Preamble Length.
The value in the prealen[8:0] register corresponds to the number of nibbles (4
bits) in the packet. For example prealen[8:0] = ‗000001000‘ corresponds to a
preamble length of 32 bits (8 x 4bits) or 4 bytes. The maximum preamble length
is prealen[8:0] = 111111111 which corresponds to a 255 bytes Preamble.
Writing 0 will have the same result as if writing 1, which corresponds to one
single nibble of preamble.
Register 35h. Preamble Detection Control 1
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
preath[4:0]
Reserved
Type
R/w
R/w
Reset value = 00101010
Bit
7：3
2:0
Name
preath[4:0]
Reserved
Function
Number of nibbles processed during detection.
Reserved.
Register 36h. Synchronization Word 3
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
sync[31:24]
Type
R/W
Reset value = 00101101
Bit
7：0
Name
sync[31:24]
Function
Synchronization Word 3.
4^th byte of the synchronization word.
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