LMX2486
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SNAS324 –JANUARY 2006
Fractional Numerator Determination { RF_FN[21:12], RF_FN[11:0], ACCESS[1] }
In the case that the ACCESS[1] bit is 0, then the part operates in 12-bit fractional mode, and the RF_FN2[21:12]
bits become do not care bits. When the ACCESS[1] bit is set to 1, the part operates in 22-bit mode and the
fractional numerator is expanded from 12 to 22-bits.
Fractional RF_FN[21:12]
RF_FN[11:0]
Numerator ( These bits only apply in 22- bit mode)
0 0 0 0 0 0 0 0 0 0 0 0 0
In 12- bit mode, these are do not care.
1 0 0 0 0 0 0 0 0 0 0 0 1
In 22- bit mode, for N <4096,
... . . . . . . . . . . . .
these bits should be all set to 0.
4095 1 1 1 1 1 1 1 1 1 1 1 1
4096 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
... . . . . . . . . . . . . . . . . . . . . . .
4194303 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Fractional Denominator Determination { RF_FD[21:12], RF_FD[11:0], ACCESS[1]}
In the case that the ACCESS[1] bit is 0, then the part is operates in the 12-bit fractional mode, and the
RF_FD[21:12] bits become do not care bits. When the ACCESS[1] is set to 1, the part operates in 22-bit mode
and the fractional denominator is expanded from 12 to 22-bits.
Fractional RF_FD[21:12] RF_FD[11:0]
Denominator ( These bits only apply in 22- bit mode)
0 In 12- bit mode, these are do not care. 0 0 0 0 0 0 0 0 0 0 0 0
In 22- bit mode, for N <4096,
1 0 0 0 0 0 0 0 0 0 0 0 1
these bits should be all set to 0.
... . . . . . . . . . . . .
4095 1 1 1 1 1 1 1 1 1 1 1 1
4096 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
... . . . . . . . . . . . . . . . . . . . . . .
4194303 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
R6 REGISTER
REGISTER 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
DATA[19:0] C C2 C1 C0
3
R6 CSR[1:0] RF_CPF[3:0] RF_TOC[13:0] 1 1 0 1
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