A power control unit activates a control signal ST for a circuit block to be
set
to a standby state before turning off power of the circuit block or a whole chip,
and saves an operation result of data processing of the circuit block into a memory
unit. When the power is again supplied to the circuit block in the standby state,
the power control unit activates a control signal RES after the power supply is
started and restores the data saved in the memory unit to the circuit block. Flip-flops
in the circuit block are connected in series when the saving or restoring of data
is performed, and perform a data transfer operation with a path different from
that in a normal operation. Therefore, a semiconductor device can be provided which
can rapidly transit to a standby mode having reduced current consumption while
holding internal information.
