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<Case of setting ftx = 433.92MHz>
ftx = 433.92MHz / fosc = 30.32MHz / fstep = 10kHz (= 3032 / 30.32MHz)
In this case, nd = 4, as frequency band is 433MHz, and the result of calculations aren't affected by f_if.
Similar to the case of frx, firstly calculate fvco based on ftx, next determine the number of NC and FC.
fvco = ftx x nd = 433.92MHz x 6 = 1732.68MHz
NC = fvco / fosc - 53 = 1735.68MHz / 30.32MHz – 53 = 4.245à NC=4 (This number is rounded to an integer.)
FC = (fvco / fosc - (NC+53)) x fosc / fstep = (1735.68MHz / 30.32MHz - (4 + 53)) x 30.32MHz / 10kHz = 744
NC = 4 à NC ="b'0100" (Binary)
FC = 744à FC ="b'00101110100" (Two's complement format)
By using those NC and FC, fvco and ftx can be calculated again.
fvco = (NC+53) x fosc + FC x fstep = (4 + 53) x 30.32MHz + 744 x 10kHz = 1735.68MHz
ftx = fvco / nd = 1735.68MHz / 4 = 433.92MHz
Notice: The change of "fosc" results the change of "fvco" in the same NC and FC.
6.10.4 h'0C VCO Frequency Settings 2
D7
Name
FC7
Initial
1
Type
R/W
[D7:D0]FC7..0 [Local Frequency: Fractional Counter]
See register h'0B section.
Table 6-59 Register (h'0C)
D6
D5
FC6
FC5
FC4
1
1
R/W
R/W
R/W
60
D4
D3
D2
FC3
FC2
1
1
R/W
R/W
TC32306FTG
D1
D0
FC1
FC0
0
0
0
R/W
R/W
2015-10-01
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