RFM22 Datasheet, PDF (47/150 Pages) –

RFM22
7.2. Modem Settings for OOK
The RFM22 is configured for OOK mode by setting the modtyp[1:0] field to OOK in "Register 71h. Modulation Mode
Control 2". In OOK mode, the following parameters can be configured: data rate, manchester coding, channel filter
bandwidth, and the clock recovery oversampling rate.
The required data rate (Rb) is configured via the txdr[15:0] field in "Register 6Eh. TX Data Rate 1" and "Register
6Fh. TX Data Rate 0". For data rates < 30 kbps, ―txdtrscale‖ in "Register 70h. Modulation Mode Control 1" should
be set to 1 for increased data rate precision. Manchester coding is enabled by setting enmanch in Register 70h.
The receive channel select filter bandwidth is configured via "Register 1Ch. IF Filter Bandwidth". The register settings
for the available channel bandwidth bandwidths are shown in Table 18.
Table 18. Channel Filter Bandwidth Settings
BW[kHz]
75.2
83.2
90
95.3
112.1
127.9
137.9
191.5
225.1
248.8
269.3
284.9
335.5
361.8
420.2
468.4
518.8
577
620.7
dwn3_bypass
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
filset[3:0]
1
2
3
4
5
6
7
F
1
2
3
4
8
9
10
11
12
13
14
The proper settings for ndec[2:0] are listed in Table 19 where Rb is the data rate (Rb) which is doubled when
Manchester coding is enabled.
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