
μ
PD784054(A)
47
10. STANDBY FUNCTION
The
μ
PD784054(A) has the following standby function modes that reduce the power consumption of the chip.
HALT mode
: This mode stops the operating clock of the CPU. It can reduce the average
power consumption through intermittent operation by combination of a normal
operation and this mode.
: This mode stops the entire system with the operation of the oscillation circuit
continuing. Normal program operation can be restored from this mode with
the power consumption close to that in the STOP mode and time equivalent
to that in the HALT mode.
: This mode stops the oscillator and stops all the internal operations of the chip
to minimize the power consumption to the level of only leakage current.
Standby function invalid mode : This mode makes the standby function (HALT/IDLE/STOP modes) invalid by
asserting the MODE1 pin high. This mode is useful when the standby mode
must not be used because of the application.
IDLE mode
STOP mode
These modes are programmable.
Macro service can be started from the HALT mode.
Figure 10-1. Standby Status Transition
Nt
HL etn
Itrutrqet
IDRESE nu
NM
Macro service request
End of first processing
End of macro service
Mcosrierqet
Edo rtpoesn
STOPsetng
RESETinpu
NM
O
scillation stabilization
time expires
Interrupt request of
masked interrupt
Macro
service
HALT
(standby)
Program
operation
Waits for
stabilization of
oscillation
IDLE
(standby)
STOP
(standby)
MODE1=L
Standby
function
invalid
MODE1=H
MODE1=H
MODE1=L
Note
Only unmasked interrupt request
Remark
Only external input of NMI is valid. The watchdog timer cannot be used to release the standby mode
(STOP/HALT/IDLE).