HD404356 Datasheet, PDF (26/100 Pages) Hitachi Semiconductor – 4-bit HMCS400-Series microcomputer

HD404358 Series
Stop
Standby
Oscillator: Stop
Peripheral clocks: Stop
All other clocks: Stop
Oscillator: Active
Peripheral clocks: Active
All other clocks: Stop
No
RESET = 0?
Yes
No
STOPC = 0?
Yes
RAME = 1
RESET = 0? ^No
Yes _{IF0 • IMO = 1? No}
Yes _{IF1 • IM1 = 1? No}
RAME = 0
Yes _{IFTA • IMTA No}
= 1?
Yes
IFTB •
No
IMTB = 1?
Yes
IFTC •
No
IMTC = 1?
Yes
IFAD • _No
IMAD = 1?
Yes
IFS •
No
IMS = 1?
Yes
Restart
processor clocks
Restart
processor clocks
Execute
next instruction
Reset MCU
No
Execute
next instruction
IF = 1,
IM = 0, and
IE = 1?
Yes
Accept interrupt
Figure 12 MCU Operation Flowchart
Stop Mode: In stop mode, all MCU operations stop and RAM data is retained. Therefore, the power
dissipation in this mode is the least of all modes. The OSC₁ and OSC₂ oscillator stops.
Stop mode is terminated by a RESET input or a STOPC input as shown in figure 13. RESET or STOPC
must be applied for at least one t_RC to stabilize oscillation (refer to the AC Characteristics section). When
the MCU restarts after stop mode is cancelled, all RAM contents before entering stop mode are retained,
but the accuracy of the contents of the accumulator, B register, W register, X/SPX register, Y/SPY register,
carry flag, and serial data register cannot be guaranteed.
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