M306H2MC-XXXFP Datasheet, PDF (37/210 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

MITSUBISHI MICROCOMPUTERS
M306H2MC-XXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
with DATA ACQUISITION CONTROLLER
2.5.5 Wait Mode
When a WAIT instruction is executed, the BCLK stops and the microcomputer enters the wait mode.
In this mode, oscillation continues but the BCLKand watchdog timer stop. Writing “1” to the WAIT
peripheral function clock stop bit and executing a WAIT instruction stops the clock being supplied to
the internal peripheral functions, allowing power dissipation to be reduced. However,peripheral func-
tion clock fC32 does not stop so that the peripherals using fC32 do not contribute to the power
saving. When the MCU running in low-speed or low power dissipation mode,do not enter WAIT mode
with this bit set to “1”. Table 2.5.3 shows the status of the ports in wait mode.
Wait mode is cancelled by a hardware reset or an interrupt. When using an interrupt to exit wait mode,
make sure the interrupt used for that purpose is enabled and those not used for that purpose have
their priority levels set to “0” before entering wait mode. When restored from wait mode by an interrupt,
the microcomputer restarts operation from the interrupt routine using as BCLK the clock with which it
was operating when the WAIT instruction was executed. When using a hardware reset or NMI inter-
rupt only, be sure to set the priority levels of all other interrupts to 0 before entering wait mode.
Table 2.5.3 Port status during wait mode
Pin
_______
_______
Address bus, data bus, CS0 to CS3
_______
BHE
_____ ______ ________ _________
RD, WR, WRL, WRH
________
HLDA, BCLK
ALE
Port
CLKOUT
When fc selected
When f8, f32 selected
Memory expansion mode
Microprocessor mode
Retains status before stop mode
“H”
“H”
“H”
Retains status before wait mode
Valid only in single-chip mode
Valid only in single-chip mode
Single-chip mode
Retains status before wait mode
Does not stop
Does not stop when the WAIT
peripheral function clock stop
bit is “0”.
When the WAIT peripheral
function clock stop bit is “1”.
the status immediately prior to
entering wait mode is maintained.
Rev. 1.0
36