Freescale Semiconductor MC68HC08KH12 - Manual (Page 106)

Advance Information MC68HC(7)08KH12 — Rev. 1.1
106 Freescale Semiconductor
MUL[11:0] — Multiplier select bits
These read/write bits control the modulo feedback divider that selects
the VCO frequency multiplier N. (See
8.4.3 PLL Circuits and 8.4.6
Programming the PLL .) MUL[11:0] cannot be written when the
PLLON bit in the PCTL is set. A value of $0000 in the multiplier select
registers configures the modulo feedback divider the same as a value
of $0001. Reset initializes the registers to $002 for a default multiply
value of 2.
NOTE: The multiplier select bits have built-in protection such that they cannot
be written when the PLL is on (PLLON = 1).
8.6.4 PLL Reference Divider Select Register (PRDS)
The PLL reference divider select register contains the programming
information for the modulo reference divider.
RDS[3:0] — Reference Divider Select Bits
These read/write bits control the modulo reference divider that selects
the reference division factor R. (See
8.4.3 PLL Circuits and 8.4.6
Programming the PLL .) RDS[7:0] cannot be written when the
PLLON bit in the PCTL is set. A value of $00 in the reference divider
select register configures the reference divider the same as a value of
$01. (See
8.4.7 Special Programming Exceptions .) Reset
initializes the register to $01 for a default divide value of 1.
NOTE: The reference divider select bits have built-in protection such that they
cannot be written when the PLL is on (PLLON = 1).
Address: $003F
Bit 7 6 5 4 3 2 1 Bit 0
Read: 0 0 0 0
RDS3 RDS2 RDS1 RDS0
Write:
Reset: 0 0 0 0 0 0 0 1
= Unimplemented
Figure 8-6. PLL Reference Divider Select Register (PRDS)