HD4048412FS datasheet(38/127 Pages) RENESAS

38 / 127 page

HD404849 Series

Stop Mode Cancellation by

STOPC : The MCU enters active mode from stop mode by inputting STOPC

RESET. In either case, the MCU starts instruction execution from the starting address (address 0) of the

program. However, the value of the RAM enable flag (RAME: $021, bit 3) differs between cancellation by

STOPC and by RESET. When stop mode is cancelled by RESET, RAME = 0; when cancelled by STOPC,

RAME = 1.

RESET can cancel all modes, but STOPC is valid only in stop mode; STOPC input is ignored

in other modes. Therefore, when the program needs to confirm that stop mode has been cancelled by

STOPC (for example, when the RAM contents before entering stop mode are used after transition to active

mode), execute the TEST instruction on the RAM enable flag (RAME) at the beginning of the program.

MCU Operation Sequence: The MCU operates in the sequence shown in figures 20 to 22. It is reset by

an asynchronous

RESET input, regardless of its status.

The low-power mode operation sequence is shown in figure 22. With the IE flag cleared and an interrupt

flag set together with its interrupt mask cleared, if a STOP/SBY instruction is executed, the instruction is

cancelled (regarded as an NOP) and the following instruction is executed. Before executing a STOP/SBY

instruction, make sure all interrupt flags are cleared or all interrupts are masked.

Power on

RESET = 0 ?

RAME = 0

Reset MCU

MCU

operation

cycle

Yes

Figure 20 MCU Operating Sequence (Power On)

HD4048412FS Datasheet(PDF) 38 Page - Renesas Technology Corp