M16C User Manual.pdf

Wait ModeMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTERWait ModeWhen a WAIT instruction is executed, the BCLK stops and the microcomputer enters the wait mode. In thismode, oscillation continues but the BCLK and watchdog timer stop. Writing “1” to the WAIT peripheralfunction clock stop bit and executing a WAIT instruction stops the clock being supplied to the internalperipheral functions, allowing power dissipation to be reduced. Table 1.13.3 shows the status of the ports inwait mode.Wait mode is cancelled by a hardware reset or an interrupt. If an interrupt is used to cancel wait mode, themicrocomputer restarts from the interrupt routine using as BCLK, the clock that had been selected when theWAIT instruction was executed.Table 1.13.3. Port status during wait modePin Memory expansion mode Single-chip mode______________Address bus, data bus, CS0 to CS3,________BHE_____ ______ ________ _________RD, WR, WRL, WRH__________HLDA,BCLKALEMicroprocessor modeRetains status before wait mode“H”“H”“H”Port Retains status before wait mode Retains status before wait modeCLKOUT When fC selected Valid only in single-chip mode Does not stopWhen f8, f32 selected Valid only in single-chip modeDoes not stop when the WAITperipheral function clock stopbit is “0”.When the WAIT peripheralfunction clock stop bit is “1”,the status immediately priorto entering wait mode is maintained.46