Rf22 – Rainbow Electronics RF22 User Manual
Page 87
RF22
Version: 0.1 Date: 12/23/2008
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7:6
trclk[1:0]
TX Data Clock Configuration.
00: No TX Data CLK is available (asynchronous mode – Can only work with modulations FSK
or OOK)
01: TX Data CLK is available via the GPIO (one of the GPIO’s should be programmed as well)
10: TX Data CLK is available via the SDO pin
11: TX Data CLK is available via the nIRQ pin
5:4
dtmod[1:0]
Modulation Source.
00: Direct Mode using TX_Data function via the GPIO pin (one of the GPIO’s should be
programmed accordingly as well)
01: Direct Mode using TX_Data function via the SDI pin (only when nSEL is high)
10: FIFO Mode
11: PN9 (internally generated)
3
eninv
Invert TX and RX Data.
2
fd[8]
MSB of Frequency Deviation Setting, see "Register 72h. Frequency Deviation".
1:0
modtyp[1:0]
Modulation Type.
00: Unmodulated carrier
01: OOK 10: FSK
11: GFSK (enable TX Data CLK (trclk[1:0]) when direct mode is used)
In TX mode, fd[8:0] (as programmed in Registers 71h and 72h) sets the transmit frequency deviation. The frequency
deviation can be calculated as Fd = 625 Hz x fd[8:0]. In RX mode, fd[8:0] sets the AFC capture range as follows:
Where the afcbd bit is set in register 1D[7].
Register 72h. Frequency Deviation
Bit
D7
D6
D5
D4 D3
D2
D1
D0
Name fd[7:0]
Type R/W
Reset value = 00100000
Bit
Name
Function
7:0
fd[7:0]
Frequency Deviation Setting.
See formula above. (see note below.)
Note: It's recommended to use modulation index of 1 or higher (maximum allowable modulation index is 32). The modulation index
is defined by
2F
N
/F
R
were F
D
is the deviation and R
B
is the data rate. When Manchester coding is enabled the
modulation index is defined by F
D
/R
B
.
The frequency offset can be calculated as Offset = 156.25 Hz x (hbsel + 1) x fo[7:0]. fo[9:0] is a twos
complement value. Reading from this register will give the AFC correction last results, not this register value.
Register 73h. Frequency Offset 1
Bit
D7
D6
D5
D4 D3
D2
D1
D0
Name fo[7:0]
Type R/W
Reset value = 00000000
Bit
Name
Function
7:0
fo[7:0]
Frequency Offset Setting.
Values written to it will be used during TX, reading from it will result in reading the last AFC
correction value.
Reading from this register will give the AFC correction last results, not this register value.