C8051F52x-53x
1.3. Operating Modes
The C8051F52x/F53x devices have four operating modes: Active (Normal), Idle, Suspend, and Stop.
Active mode occurs during normal operation when the oscillator and peripherals are active. Idle mode halts
the CPU while leaving the peripherals and internal clocks active. In Suspend and Stop mode, the CPU is
halted, all interrupts and timers are inactive, and the internal oscillator is stopped. The various operating
modes are described in Table 1.2 below:
Table 1.2. Operating Modes Summary
Power
Consumption
How
Entered?
Properties
SYSCLK active
How Exited?
•
•
•
Full
—
—
CPU active (accessing Flash)
Peripherals active or inactive
depending on user settings
Active
Idle
•
•
SYSCLK active
CPU inactive (not accessing
Flash)
Less than Full
IDLE
(PCON.0)
Any enabled interrupt
or device reset
•
Peripherals active or inactive
depending on user settings
•
•
Internal oscillator inactive
If SYSCLK is derived from the
internal oscillator, the peripher-
als and the CIP-51 will be
stopped
Low
SUSPEND
(OSCICN.5)
Port 0 event match
Port 1 event match
Comparator 0 enabled
and output is logic ‘0’
Suspend
Stop
•
•
SYSCLK inactive
CPU inactive (not accessing
Flash)
Digital peripherals inactive; ana-
log peripherals active or inactive
depending on user settings
Very low
STOP
(PCON.1)
Device Reset
•
See Section “9.3. Power Management Modes” on page 83 for Idle and Stop mode details. See Section
“15.1.1. Internal Oscillator Suspend Mode” on page 134 for more information on Suspend mode.
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Rev. 0.3
SILICON [ SILICON ]
