Let's have a look at how to set each related register and bit when entering the Wait Mode.

• Setting an Interrupt for Leaving Wait Mode

Set an interrupt, which is used to place the MCU out of the Wait Mode. Make sure the priority level set for this interrupt is higher than the Processor Interrupt Priority Level (IPL).

• Enabling the Interrupt Enable Flag (I Flag)

Set the Interrupt Enable Flag (I Flag) in the Flag Register (FLG) to 1 in order to enable all maskable interrupts.

• Removing Protection

Set the bit for writing-enable to System Clock Control Registers 0 and 1 that is assigned in the Protect Register (address 0000A) to 1 in order to remove protection from these two registers.

• Setting the System Clock Control Registers 0 and 1

Set the operating clock to be used after returning from the Wait Mode. Unless these registers are specifically modified, BCLK is selected that was being used before entering the Wait Mode. Set the WAIT Peripheral Function Clock Stop Bit to 1 in order to turn the peripheral functions off.

• Executing the WAIT Instruction

Execute the WAIT instruction to place the MCU into the Wait Mode. The MCU is placed out of the Wait Mode by an interrupt or hardware reset. After leaving the Wait Mode, the MCU starts operating with BCLK that was being used before entering the Wait Mode.