M37902FCCHP, M37902FGCHP, M37902FJCHP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
94
Fig. 100 Bit configuration of particular function select register 0
Fig. 99 Bit configuration of clock control register
7
6
543
2
1
0
Clock control register
Fix this bit to “1”.
PLL circuit operation enable bit (Note 1)
0: PLL frequency multiplier is stopped, and pin VCONT is invalid (floating state).
1: PLL frequency multiplier is operating, and pin VCONT is valid.
PLL multiplication ratio select bits (Note 2)
00: Do not select.
01: Double
10: Triple
11: Quadruple
Fix this bit to “0”.
System clock select bit (Note 3)
0: fXIN
1: fPLL
Peripheral device’s clock select bits 1, 0
See Table 16.
Address
BC16
1
0
At reset
0716
Notes 1: When not using the PLL frequency multiplier, clear this bit to “0”. In the stop mode or in
the flash memory parallel I/O mode, the PLL circuit stops it’s operation regardless of this
bit’s contents; at this time, pin VCONT is invalid.
2: When rewriting this bit, be sure to clear bit 5 to “0” simultaneously. Also, after this bit is
rewritten, insert a waiting time of 2 ms, and then set bit 5 to “1”.
3: When the PLL circuit operation enable bit (bit 1) has been cleared to “0”, this bit will also
be cleared to “0”. Also, bit 1 = “0”, nothing can be written to this bit. (Fixed to be “0”.)
7
6
543
2
1
0
Particular function select register 0
External clock input select bit (Note)
0: Oscillation circuit is active. (Oscillator is connected.)
Watchdog timer is used at stop mode termination.
1: Oscillation circuit is inactive. (External clock is input.)
When the system clock select bit = “0”,
watchdog timer is not used at stop mode termination.
When the system clock select bit = “1”,
watchdog timer is used at stop mode termination.
Fix this bit to “0”.
STP instruction invalidity select bit (Note)
0: STP instruction is valid.
1: STP instruction is invalid.
Note:
Address
6216
0
Writing to these bits requires the following procedure:
Write “5516” to this register. (The bit status does not change only by this writing.)
Succeedingly, write “0” or “1” to each bit.
Also, use the MOVM (MOVMB) instruction or STA (STAB, STAD) instruction