Under
development
Preliminary Specifications REV.B3
Specifications in this manual are tentative and subject to change.
Mitsubishi Microcomputers
M32C/83 group
SINGLE-CHIP 16/32-BIT CMOS MICROCOMPUTER
78
Power Saving
(3) Stop mode
All oscillation, main clock, subclock, and PLL synthesizer stop in this mode. Because the oscillation of
BCLK and peripheral clock stops in stop mode, peripheral functions such as the A-D converter, timer A
and B, serial I/O, intelligent I/O and watchdog timer do not function.
The content of the internal RAM is retained provided that VCC remains above 2.5V.
When changing to stop mode, the main clock division register (000C16) is set to “XXX010002” (division by
8 mode).
(a) Changing to stop mode
All clock stop control bit of system clock control register 1 (bit 0 at address 000716)
0: Clock ON
1: All clocks off (stop mode)
Before changing to stop mode, set bit 7 of PLL control register 0 (address 037616) to "0" to stop PLL.
Also, set bit 0 of VDC control register for PLL (address 001716) to "1" to turn PLL circuit power off.
(b) The status of the ports in stop mode
Table 1.8.7 shows the status of the ports in stop mode.
(c) Exit from stop mode
Stop mode is cancelled by a hardware reset or interrupt. If a peripheral function interrupt is used to
cancel stop mode, set the following registers.
Interrupt priority set bits for exiting a stop/wait state of exit priority register (bits 0 to 2 at address 009F16) :RLVL0 to RLVL2
Set the same level as the flag register (FLG) processor interrupt level (IPL).
Interrupt priority set bits of interrupt control register (bits 0 to 2)
Set to a priority level above the level set by RLVL0 to RLVL2 bits
Interrupt enable flag of FLG register
I = 1
When exiting from stop mode using peripheral interrupt request, CPU operates the following BCLK
and the relevant interrupt routine is executed.
When subclock was set as BCLK before changing to stop mode, subclock is set to BCLK after
cancelled stop mode
When main clock was set as BCLK before changing to stop mode, the main clock division by 8 is set
to BCLK after cancelled stop mode.
Table 1.8.7. Port status during stop mode
Pin
Memory expansion mode
Single-chip mode
Microprocessor mode
_______
Address bus, data bus, CS0 to CS3, BHE
Retains status before stop mode
_____
______
________
_________
______
_________
________
RD, WR, WRL, WRH, DW, CASL, CASH
“H” (Note)
________
RAS
“H” (Note)
__________
HLDA, BCLK
“H”
ALE
“H”
Port
Retains status before stop mode
CLKOUT
When fc selected
“H”
When f8, f32 selected
Retains status before stop mode
________
Note :When self-refresh is done in operating DRAM control, CAS and RAS becomes “L”.