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FUJITSU F2MCTM-16LX User Manual

Page 118

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102

CHAPTER 5 CLOCKS

Table 5.4-1 Functional Description of Each Bit in the PLL/subclock Control Register (PSCCR)

Bit name

Function

bit15
to
bit12

Unused

These bits are not used.
Writing to these bits has no effect to operation.
Read value is always "1".

bit11

Reserved bit

Always write "0" to this bit.
Read value is always "1".

bit10 SCDS:

Subclock
division selection
bit

The division ratio of the subclock is selected.
When "0" is written to this bit, 4 division is selected.
When "1" is written to this bit, 2 division is selected.
Read value is always "1".
This bit is initialized to "0" by all reset causes.

bit9

Reserved bit

Always write "0" to this bit.
Read value is always "1".

bit8 CS2:

Multiplication
rate selection bit

This bit and CS1 and CS0 bits of the clock selection register (CKSCR) determine the PLL
multiplication rate.

CS2

CS1

CS0

PLL clock multiplication rate

0

0

0

Ч 1

0

0

1

Ч 2

0

1

0

Ч 3

0

1

1

Ч 4

1

1

0

Ч 6

1

1

1

Setting disabled

Read value is always "1".
This bit is initialized to "0" by all reset causes.
Note: When MCS or MCM bit is "0", setting CS2 to CS0 to "111

B

" is prohibited.

When CKSCR: CS1 and CS0 is set to "11

B

", do not set "1" to this bit.

Note: PSCCR register is write-only register. Read value is different from writing value. Do not use the RMW instruction

(SETB/CLRB instruction).