C8051F85X86X Datasheet, PDF (22/290 Pages) Silicon Laboratories – Low-Cost 8-bit MCU Family with up to 8 kB of Flash

C8051F85x/86x
2.1. Power
2.1.1. LDO
The C8051F85x/86x devices include an internal regulator to regulate the supply voltage down the core operating
voltage of 1.8 V. This LDO consumes little power, but can be shut down in the power-saving Stop mode.
2.1.2. Voltage Supply Monitor (VMON0)
The C8051F85x/86x devices include a voltage supply monitor which allows devices to function in known, safe
operating condition without the need for external hardware.
The supply monitor module includes the following features:
Holds the device in reset if the main VDD supply drops below the VDD Reset threshold.
2.1.3. Device Power Modes
The C8051F85x/86x devices feature three low power modes in addition to normal operating mode, allowing the
designer to save power when the core is not in use. All power modes are detailed in Table 2.1.
Mode
Normal
Idle
Stop
Shutdown
Table 2.1. C8051F85x/86x Power Modes
Description
Mode Entrance
Mode Exit
Core and peripherals operating
at full speed
Core halted
Peripherals operate at
full speed
Set IDLE bit in PCON
All clocks stopped
Core LDO and
(optionally)
comparators still
running
Pins retain state
Clear STOPCF in REG0MD
and
Set STOP bit in PCON
All clocks stopped
Core LDO and all
analog circuits shut
down
Pins retain state
Set STOPCF in REG0MD
and
Set STOP bit in PCON
Any enabled interrupt or
reset source
Device reset
Device reset
In addition, the user may choose to lower the clock speed in Normal and Idle modes to save power when the CPU
requirements allow for lower speed.
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Preliminary Rev 0.6