CHAPTER 8 CLOCK GENERATION FUNCTION
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User’s Manual U14492EJ3V0UD
8.5.4 IDLE mode
(1) Setting and operation status
In IDLE mode, the clock generator (oscillator and PLL synthesizer) continues to operate, but the supply of
internal system clocks is stopped which causes the overall system to stop.
When IDLE mode is released, the system can be switched to normal operation mode quickly because the
oscillator’s oscillation stabilization time or the PLL lockup time need not be secured.
The system is switched to IDLE mode by setting the PSC or PSMR register using a store instruction (ST or
SST instruction) or a bit manipulation instruction (SET1, CLR1, or NOT1 instruction) (see
8.5.2 Control
registers
).
In IDLE mode, program execution is stopped, and the contents of all registers, internal RAM, and ports are
maintained in the state they were in immediately before execution stopped. The operation of on-chip
peripheral I/O units (excluding ports) also is stopped.
Table 8-4 shows the status of each hardware unit in IDLE mode.
Table 8-4. Operation Status in IDLE Mode
Function
Operation Status
Clock generator
Operating
Internal system clock
Stopped
CPU
Stopped
Ports
Maintained
On-chip peripheral I/O (excluding ports)
Stopped
Note
Internal data
All internal data such as CPU registers, statuses, data,
and the contents of internal RAM are maintained in the
state they were in immediately before IDLE mode
began.
AD0 to AD15
A16 to A23
High impedance
RD
UWR, LWR
CS0 to CS7
High-level output
HLDAK
High impedance
HLDRQ
WAIT
Input (no sampling)
ASTB
High-level output
CLKOUT
Low-level output
Note
NBD cannot be used in IDLE mode.
Содержание V850E/IA1 mPD703116
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