m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 479

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

APPENDIX
Appendix 2. Control registers
20-48
Clock control register
Notes 1: Clear this bit to “0” if the PLL frequency multiplier needs not to be active.
Bit
0
1
2
3
4
5
6
7
2: Rewriting of these bits must be performed simultaneously with clearance of the system clock select bit (bit 5) to “0.”
3: Clearance of the PLL circuit operation enable bit (bit 1) to “0” clears the system clock select bit to “0.” Also, while the PLL
Then, set bit 5 to “1” 2 ms after the rewriting of these bits. (After reset, these bits are allowed to be changed only once.)
In the stop and flash memory parallel I/O modes, the PLL frequency multiplier is inactive and pin V
less of the contents of this bit.
circuit operation enable bit = “0,” nothing can be written to the system clock select bit. (Fixed to be “0.”)
Before setting of the system clock select bit to “1” after reset, it is necessary to insert an interval of 2 ms after the
stabilization of f(X
Fix this bit to “1.”
PLL circuit operation enable bit
(Note 1)
PLL multiplication ratio select bits
(Note 2)
Fix this bit to “1.”
System clock select bit
Peripheral device’s clock select bit 0
Peripheral device’s clock select bit 1
Bit name
0 (Address BC
IN
).
(Note 3)
16
)
7905 Group User’s Manual Rev.1.0
0 : PLL frequency multiplier is inactive, and pin V
1 : PLL frequency multiplier is active, and pin V
b3 b2
0 0 : Do not select.
0 1 :
1 0 :
1 1 :
0 : fX
1 : f
See Table 4.2.2.
is invalid. (Floating)
PLL
IN
2
3
4
Function
CONT
b7 b6 b5 b4 b3 b2 b1 b0
is valid.
CONT
CONT
1
At reset
is invalid regard-
1
1
1
0
1
0
0
0
R/W
RW
RW
RW
RW
RW
RW
RW
RW
1
Reference
4-6
4-7