Texas Instruments MSP430x4xx - Manual (Page 121)

FLL+ Clock Module Registers
4-12 FLL+ Clock Module
SCFQCTL, System Clock Control Register
7 6 5 4 3 2 1 0
SCFQ_M N
rw−0 rw−0 rw−0 rw−1 rw−1 rw−1 rw−1 rw−1
SCFQ_M Bit 7 Modulation. This enables or disables modulation
0
Modulation enabled
1 Modulation disabled
N Bits
6-0 Multiplier. These bits set the multiplier value for the DCO. N must be > 0 or
unpredictable operation will result.
When DCOPLUS=0: f
DCOCLK
= (N + 1)
⋅
f
crystal
When DCOPLUS=1: f
DCOCLK
= D x (N + 1)
⋅
f
crystal
SCFI0, System Clock Frequency Integrator Register 0
7 6 5 4 3 2 1 0
FLLDx FN_x MODx (LSBs)
rw−0 rw−1 rw−0 rw−0 rw−0 rw−0 rw−0 rw−0
FLLDx Bits
7-6 FLL+ loop divider. These bits divide f
DCOCLK
in the FLL+ feedback loop.
This results in an additional multiplier for the multiplier bits. See also multi-
plier bits.
00
/1
01 /2
10 /4
11 /8
FN_x Bits
5-2 DCO Range Control. These bits select the f
DCO
operating range.
0000 0.65 - 6.1 MHz
0001 1.3 - 12.1 MHz
001x 2 - 17.9 MHz
01xx 2.8 - 26.6 MHz
1xxx 4.2 - 46 MHz
MODx Bits
1−0 Least significant modulator bits. Bit 0 is the modulator LSB. These bits
affect the modulator pattern. All MODx bits are modified automatically by
the FLL+.