Rainbow Electronics RF22 - Manual (Page 88)

RF22
Version: 0.1 Date: 12/23/2008
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Register 74h. Frequency Offset 2
Bit D7 D6 D5 D4 D3 D2 D1 D0
Name Reserved fo[9:8]
Type R R/W
Reset value = 00000000
Bit Name Function
7:2 Reserved Reserved.
1:0 fo[9:8] Upper Bits of the Frequency Offset Setting.
fo[9] is the sign bit. Values written to it will be used during TX, reading from it will result in
reading the last AFC correction value.
Register 75h. Frequency Band Select
Bit D7 D6 D5 D4 D3 D2 D1 D0
Name Reserved sbsel hbsel fb[4:0]
Type R R/W R/W R/W
Reset value = 01110101
Bit Name Function
7 Reserved Reserved.
6 sbsel Side Band Select.
5 hbsel High Band Select.
Setting hbsel = 1 will choose the frequency range from 480–960 MHz (high bands). Setting
hbsel = 0 will choose the frequency range from 240–479.9 MHz (low bands).
4:0 fb[4:0] Frequency Band Select.
Every increment corresponds to a 10 MHz Band for the Low Bands and a 20 MHz Band for the
High Bands.
Setting fb[4:0] = 00000 corresponds to the 240–250 MHz Band for hbsel = 0 and the 480–500
MHz Band for hbsel = 1.
Setting fb[4:0] = 00001 corresponds to the 250–260 MHz Band for hbsel = 0 and the 500–520
MHz Band for hbsel = 1.
The RF carrier frequency can be calculated as follows:
f
carrier = (f b +24+(f c +f o ) / 64000) x 10000 x (hbsel+1) + (f hch x f hs x 10) [kHz],
where parameters f c , f o , f b and hb_sel come from registers 73h–77h. Parameters f hch and f hs come from register 79h
and 7Ah.
Register 76h. Nominal Carrier Frequency
Bit D7 D6 D5 D4 D3 D2 D1 D0
Name fc[15:8]
Type R/W
Reset value = 10111011
Bit Name Function
7:0 fc[15:8] Nominal Carrier Frequency Setting.
See formula above.
Register 77h. Nominal Carrier Frequency
Bit D7 D6 D5 D4 D3 D2 D1 D0
Name fc[7:0]
Type R/W
Reset value = 10000000
Bit Name Function
7:0 fc[7:0] Nominal Carrier Frequency Setting.
See formula above.