CHAPTER 5 CLOCK GENERATOR
Preliminary User’s Manual U19014EJ1V0UD
92
(8) PLL control register (PLLC)
This register sets the operation mode of PLL.
PLLC can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation sets this register to 01H.
Figure 5-9. Format of PLL Control Register (PLLC)
Address: FFA6H After reset: 01H R/W
Symbol
7 6 5 4 3 2
<1>
<0>
PLLC
0 0 0 0 0 0
PLLM
PLLSTOP
Selection of multiplication ratio for clock supplied to PLL/PLL
XSEL PLLM
Supply clock
Multiplication ratio selection
0
0
Setting prohibited
Setting prohibited
1
Setting prohibited
Setting prohibited
1
0
f
XH
/2 x8
Note 1
1
f
XH
/4 x12
Note 2
PLLSTOP
PLL
operation
control
0
PLL
oscillating
1
PLL
stopped
Notes 1.
f
USB
= 48 MHz when f
XH
= 12 MHz.
2.
f
USB
= 48 MHz when f
XH
= 16 MHz.
Cautions. When using the USB function, set the clock supplied to PLL as initial setting after
reset.
<Setting
procedure>
<1>
Stop PLL. (PLLSTOP=1)
<2>
Select PLLM (0: f
XH
=12 MHz 1: f
XH
=16 MHz ).
<3 >
Set XSEL to 1.
<4>
enable PLL driven. (PLLSTOP=0)
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