M16C Datasheet, PDF (45/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Mitsubishi microcomputers
Specifications in this manual are tentative and subject to change.
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
CStloactuksGTerannesraittioinngoCf iBrcCuLitK
Status Transition Of BCLK
Power consumption can be reduced and low-voltage operation achieved by changing the count source for
BCLK. Table 5-4 shows the operating modes corresponding to the settings of system clock control registers
0 and 1.
After a reset, operation defaults to division by 8 mode. When shifting to stop mode, the main clock division
select bit 0 (bit 6 at address 000616) is set to “1”. The following shows the operational modes of BCLK.
(1) Division by 2 mode
The main clock is divided by 2 to obtain the BCLK.
(2) Division by 4 mode
The main clock is divided by 4 to obtain the BCLK.
(3) Division by 8 mode
The main clock is divided by 8 to obtain the BCLK. Note that oscillation of the main clock must have
stabilized before transferring from this mode to another mode.
(4) Division by 16 mode
The main clock is divided by 16 to obtain the BCLK.
(5) No-division mode
The main clock is used as BCLK.
(6) Low-speed mode
fC is used as BCLK. Note that oscillation of both the main and sub clocks must have stabilized before
transferring from this mode to another or vice versa. At least 2 to 3 seconds are required after the sub clock
starts. Therefore, the program must be written to wait until this clock has stabilized immediately after
powering up and after stop mode is cancelled.
(7) Low power consumption mode
fC is the BCLK and the main clock is stopped.
(8) Ring oscillator mode
What the ring oscillator generates is the BCLK. You can use it by dividing it by 2, 4, 8 or 16, and also no
division is possible.
Table 5-4. Operating modes dictated by settings of system clock control registers 0 and 1
CM17
0
1
Invalid
1
0
Invalid
Invalid
CM16
1
0
Invalid
1
0
Invalid
Invalid
CM07
0
0
0
0
0
1
1
CM06
0
0
1
0
0
Invalid
Invalid
CM05
0
0
0
0
0
0
1
CM04
Invalid
Invalid
Invalid
Invalid
Invalid
1
1
Operating mode of BCLK
Division by 2 mode
Division by 4 mode
Division by 8 mode
Division by 16 mode
No-division mode
Low-speed mode
Low power consumption mode
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