NXP Semiconductors
LPC178x/7x
32-bit ARM Cortex-M3 microcontroller
On the wake-up of Power-down mode, if the IRC was used before entering Power-down
mode, it will take IRC 60 s to start-up. After this, four IRC cycles will expire before the
code execution can then be resumed if the code was running from SRAM. In the
meantime, the flash wake-up timer then counts 12 MHz IRC clock cycles to make the
100 s flash start-up time. When it times out, access to the flash will be allowed. Users
need to reconfigure the PLL and clock dividers accordingly.
7.33.4.4 Deep power-down mode
In Deep power-down mode, power is shut off to the entire chip with the exception of the
RTC module and the RESET pin.
To optimize power conservation, the user has the additional option of turning off or
retaining power to the 32 kHz oscillator. It is also possible to use external circuitry to turn
off power to the on-chip regulator via the VDD(REG)(3V3) pins and/or the I/O power via the
VDD(3V3) pins after entering Deep Power-down mode. Power must be restored before
device operation can be restarted.
The LPC178x/7x can wake up from Deep power-down mode via the RESET pin or an
alarm match event of the RTC.
7.33.4.5 Wake-up Interrupt Controller (WIC)
The WIC allows the CPU to automatically wake up from any enabled priority interrupt that
can occur while the clocks are stopped in Deep-sleep, Power-down, and Deep
power-down modes.
The WIC works in connection with the Nested Vectored Interrupt Controller (NVIC). When
the CPU enters Deep-sleep, Power-down, or Deep power-down mode, the NVIC sends a
mask of the current interrupt situation to the WIC.This mask includes all of the interrupts
that are both enabled and of sufficient priority to be serviced immediately. With this
information, the WIC simply notices when one of the interrupts has occurred and then it
wakes up the CPU.
The WIC eliminates the need to periodically wake up the CPU and poll the interrupts
resulting in additional power savings.
7.33.5 Peripheral power control
A power control for peripherals feature allows individual peripherals to be turned off if they
are not needed in the application, resulting in additional power savings.
7.33.6 Power domains
The LPC178x/7x provide two independent power domains that allow the bulk of the
device to have power removed while maintaining operation of the RTC and the backup
registers.
On the LPC178x/7x, I/O pads are powered by VDD(3V3), while VDD(REG)(3V3) powers the
on-chip voltage regulator which in turn provides power to the CPU and most of the
peripherals.
Depending on the LPC178x/7x application, a design can use two power options to
manage power consumption.
LPC178X_7X
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 5.5 — 26 April 2016
© NXP Semiconductors N.V. 2016. All rights reserved.
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