MC908AP32CFBE Datasheet, PDF (92/324 Pages) Freescale Semiconductor, Inc – The following revision history table summarizes changes contained in this document. For your convenience, the page number designators have been linked to the appropriate location.

Clock Generator Module (CGM)
6.5.3 PLL Multiplier Select Registers
The PLL multiplier select registers (PMSH and PMSL) contain the programming information for the
modulo feedback divider.
Address:
Read:
Write:
Reset:
$0038
Bit 7
6
5
4
3
2
1
0
0
0
0
MUL11 MUL10 MUL9
0
0
0
0
0
0
0
= Unimplemented
Figure 6-6. PLL Multiplier Select Register High (PMSH)
Bit 0
MUL8
0
Address:
Read:
Write:
Reset:
$0039
Bit 7
6
5
4
3
2
1
MUL7
MUL6
MUL5
MUL4
MUL3
MUL2
MUL1
0
1
0
0
0
0
0
Figure 6-7. PLL Multiplier Select Register Low (PMSL)
Bit 0
MUL0
0
MUL[11:0] — Multiplier Select Bits
These read/write bits control the modulo feedback divider that selects the VCO frequency multiplier N.
(See 6.3.3 PLL Circuits and 6.3.6 Programming the PLL.) A value of $0000 in the multiplier select
registers configure the modulo feedback divider the same as a value of $0001. Reset initializes the
registers to $0040 for a default multiply value of 64.
NOTE
The multiplier select bits have built-in protection such that they cannot be
written when the PLL is on (PLLON = 1).
6.5.4 PLL VCO Range Select Register
The PLL VCO range select register (PMRS) contains the programming information required for the
hardware configuration of the VCO.
Address:
Read:
Write:
Reset:
$003A
Bit 7
6
5
4
3
2
1
VRS7
VRS6
VRS5
VRS4
VRS3
VRS2
VRS1
0
1
0
0
0
0
0
Figure 6-8. PLL VCO Range Select Register (PMRS)
Bit 0
VRS0
0
VRS[7:0] — VCO Range Select Bits
These read/write bits control the hardware center-of-range linear multiplier L which, in conjunction with
E (See 6.3.3 PLL Circuits, 6.3.6 Programming the PLL, and 6.5.1 PLL Control Register.), controls the
hardware center-of-range frequency, f_VRS. VRS[7:0] cannot be written when the PLLON bit in the
PCTL is set. (See 6.3.7 Special Programming Exceptions.) A value of $00 in the VCO range select
MC68HC908AP Family Data Sheet, Rev. 4
92
Freescale Semiconductor