M16C26A Datasheet, PDF (71/352 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/26A Group (M16C/26A, M16C/26B, M16C/26T)
7. Clock Generation Circuit
Figure 7.6.1 shows the state transition from normal operation mode to stop mode and wait mode. Figure
7.6.1.1 shows the state transition in normal operation mode.
Table 7.6.1 shows a state transition matrix describing allowed transition and setting. The vertical line
shows current state and horizontal line shows state after transition.
All oscillators stopped
Stop mode
CM10=1⁽⁶⁾
Interrupt
CM07=0
CM06=1
CM05=0
CM11=0
CM10=1
(5)
Interrupt
Stop mode
CM10=1⁽⁶⁾
Stop mode
Stop mode
Stop mode
CM10=1⁽⁶⁾
Interrupt
CM10=1⁽⁶⁾
Interrupt
CM10=1⁽⁶⁾
CM21=0
Interrupt⁽⁴⁾
Normal operation mode
Medium-speed mode
(divided-by-8 mode)
High-speed, medium-
speed mode
(1, 2)
PLL operation
mode
Low-speed mode
(7)
Low power dissipation mode
On-chip oscillator low power
dissipation mode
WAIT
instruction
Interrupt
WAIT
instruction
Interrupt
CPU operation stopped
Wait mode
Wait mode
WAIT
instruction
Interrupt
WAIT
instruction
CM21=1
Interrupt
WAIT
instruction
Interrupt
Wait mode
Wait mode
Wait mode
Stop mode
CM10=1⁽⁶⁾
Interrupt⁽⁴⁾
On-chip oscillator mode
(selectable frequency)
On-chip oscillator
mode (f_2(ROC)/16)
WAIT
instruction
Interrupt
Wait mode
CM05, CM06, CM07: Bits in the CM0 register
CM10, CM11: Bits in the CM1 register
Reset
: Arrow shows mode can be changed. Do not change mode to another mode when no arrow is shown.
NOTES:
1. Do not go directly from PLL operation mode to wait or stop mode.
2. PLL operation mode can be entered from high speed mode. Similarly, PLL operation mode can be changed back to high speed mode.
3. When the PM21 bit is set to 0 (system clock protective function unused).
4. The on-chip oscillator clock divided by 8 provides the CPU clock.
5. Write to the CM0 register and CM1 register simultaneously by accessing in word units while CM21 bit is set to 0 (on-chip oscillator
turned off). When the clock generated externally is input to the XCIN pin, transit to stop mode with this process.
6. Before entering stop mode, be sure to clear the CM20 bit in the CM2 register to 0 (oscillation stop and oscillation restart detection
function disabled).
7. The CM06 bit is set to 1 (divide-by-8).
Figure 7.6.1. State Transition to Stop Mode and Wait Mode
Rev. 2.00 Feb.15, 2007 ^{page 54} of 329
REJ09B0202-0200