M30222 Datasheet, PDF (26/237 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
Specifications in this manual are tentative and subject to change
M30222 Group
Rev. G
Stop Mode
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Stop Mode
Writing "1" to all-clock stop control bit (bit 0 at address 000716) stops all oscillation and the microcom-
puter enters stop mode. In stop mode, the content of the internal RAM is retained provided that VCC
remains above 2V.
Because the oscillation , BCLK, f1 to f32, fC, fC132, fC1, fC32 and fAD stops in stop mode, peripheral
functions such as the A-D converter and watchdog timer do not function. However, Timer A and Timer
B operate provided that the event counter mode is set to an external pulse, and UART0 to UART2
functions provided an external clock is selected. Table 1.12 shows the status of the ports in stop mode.
Stop mode is cancelled by a hardware reset or an interrupt. If an interrupt is to be used to cancel stop
mode, that interrupt must first have been enabled. If coming out of stop mode is caused by an interrupt,
that interrupt routine is executed.
When shifting from high-speed/medium-speed mode to stop mode and at a reset, the main clock divi-
sion select bit 0 (bit 6 at address 000616) is set to “1”. When shifting from low-speed/low power dissipa-
tion mode to stop mode, the value before stop mode is retained.
Usage Precautions
(1) When returning from stop mode by hardware reset, RESET pin must be set to “L” level until main clock
oscillation is stabilized.
(2) When switching to either wait mode or stop mode, instructions occupying four bytes either from the WAIT
instruction or from the instruction that sets the every-clock stop bit to “1” within the instruction queue are
prefetched and then the program stops. Put at least four NOPs in succession either to the WAIT instruction or
to the instruction that sets the every-clock stop bit to “1”.
Table 1.12 Port status during stop mode
Pin
Port
CLKOUT/
P75
Mode
When fc1 selected
When f1, clock divided
output selected
Status
Retains status before stop mode
"H"
Retains status before stop mode
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