Mitsubishi microcomputers
M16C / 62P Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Clock Generation Circuit
56
development
Preliminary Specifications Rev.1.0
Specifications in this manual are tentative and subject to change.
Figure 1.9.5. PCLKR Register and PM2 Register
Function
Bit symbol
Bit name
Peripheral clock select register (Note)
Symbol
PCLKR
Address
025E
16
When reset
00000011
2
RW
b7
0
b6
0 0
b5
b4
0
b3
0 0
b2
b1
b0
PCLK0
Timers A, B clock select bit
(Clock source for the
timers A, B, and the dead
time timer)
0 : f
2
1 : f
1
Reserved bit
Must set to
“0”
Note: Write to this register after setting the PRC0 bit of PRCR register to “1” (write enable).
PCLK1
SI/O clock select bit
(Clock source for UART0
to UART2, SI/O3, SI/O4)
0 : f
2SIO
1 : f
1SIO
RW
RW
RW
(b7-b2)
Function
Bit symbol
Bit name
Processor mode register 2 (Note 1)
Symbol
PM2
Address
001E
16
After reset
XXX00000
2
RW
b7 b6 b5 b4 b3 b2 b1 b0
0
PM20
Specifying wait when
accessing SFR at PLL
operation
System clock protective
bit
(Note 3, Note 4)
0 : 2 waits
1 : 1 wait
0
Reserved bit
Must set to “0”
Nothing is assigned. When write, set to “0”. When read, its
content is interdeterminate.
Note 1: Write to this register after setting the PRC1 bit of PRCR register to “1” (write enable).
Note 2: This bit can only be rewritten while the PLC07 bit is “0” (PLL turned off). Also, to select a 16 MHz or higher PLL
clock, set this bit to “0” (2 waits). Note that if the clock source for the CPU clock is to be changed from the PLL
clock to another, the PLC07 bit must be set to “0” before setting the PM20 bit.
Note 3: Once this bit is set to “1”, it cannot be cleared to “0” in a program.
Note 4: Setting the PM21 bit to “1” results in the following conditions:
The BCLK is not halted by executing the WAIT instruction.
Writing to the following bits has no effect.
CM02 bit of CM0 register
CM05 bit of CM0 register (main clock is not halted)
CM07 bit of CM0 register (CPU clock source does not change)
CM10 bit of CM1 register (stop mode is not entered)
CM11 bit of CM1 register (CPU clock source does not change)
CM20 bit of CM2 register (oscillation stop, re-oscillation detection function settings do not change)
All bits of PLC0 register (PLL frequency synthesizer settings do not change)
Note 5: Setting the PM22 bit to “1” results in the following conditions:
The ring oscillator starts oscillating, and the ring oscillator clock becomes the watchdog timer count source.
The CM10 bit of CM1 register is disabled against write. (Writing a “1” has no effect, nor is stop mode
entered.)
The watchdog timer does not stop when in wait mode or hold state.
(Note 2)
RW
RW
RW
PM21
(b7-b5)
0 : Clock is protected by PRCR
register
1 : Clock modification disabled
0 : CPU clock is used for the
watchdog timer count source
1 : Ring oscillator clock is used
for the watchdog timer count
source
PM22
WDT count source
protective bit
(Note 3, Note 5)
RW
(b4-b3)