lpc2361 NXP Semiconductors, lpc2361 Datasheet - Page 29

• Manufacturer Part Number: lpc2361
• Description: Single-chip 16-bit/32-bit Mcu; Up To 128 Kb ?ash With Isp/iap, Ethernet, Usb 2.0 Device/host/otg, Can, And 10-bit Adc/dac
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2361_62_3
Product data sheet
7.23.4.3 Power-down mode
7.23.4.4 Power domains
32 kHz RTC oscillator is not stopped because the RTC interrupts may be used as the
wake-up source. The PLL is automatically turned off and disconnected. The CCLK and
USB clock dividers automatically get reset to zero.
The Sleep mode can be terminated and normal operation resumed by either a Reset or
certain specific interrupts that are able to function without clocks. Since all dynamic
operation of the chip is suspended, Sleep mode reduces chip power consumption to a
very low value. The flash memory is left on in Sleep mode, allowing a very quick wake-up.
On the wake-up of Sleep mode, if the IRC was used before entering Sleep mode, the code
execution and peripherals activities will resume after 4 cycles expire. If the main external
oscillator was used, the code execution will resume when 4096 cycles expire.
The customers need to reconfigure the PLL and clock dividers accordingly.
Power-down mode does everything that Sleep mode does, but also turns off the IRC
oscillator and the flash memory. This saves more power, but requires waiting for
resumption of flash operation before execution of code or data access in the flash memory
can be accomplished.
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 4 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 4 MHz IRC clock cycles to make the 100 s flash start-up
time. When it times out, access to the flash will be allowed. The customers need to
reconfigure the PLL and clock dividers accordingly.
The LPC2361/62 provides two independent power domains that allow the bulk of the
device to have power removed while maintaining operation of the RTC and the battery
RAM.
On the LPC2361/62, I/O pads are powered by the 3.3 V (V
V
the CPU and most of the peripherals.
Depending on the LPC2361/62 application, a design can use two power options to
manage power consumption.
The first option assumes that power consumption is not a concern and the design ties the
V
supply for both pads, the CPU, and peripherals. While this solution is simple, it does not
support powering down the I/O pad ring “on the fly” while keeping the CPU and
peripherals alive.
The second option uses two power supplies; a 3.3 V supply for the I/O pads (V
a dedicated 3.3 V supply for the CPU (V
converter powered independently from the I/O pad ring enables shutting down of the I/O
pad power supply “on the fly”, while the CPU and peripherals stay active.
DD(DCDC)(3V3)
DD(3V3)
and V
pin powers the on-chip DC-to-DC converter which in turn provides power to
DD(DCDC)(3V3)
Rev. 03 — 11 November 2008
pins together. This approach requires only one 3.3 V power
DD(DCDC)(3V3)
). Having the on-chip DC-to-DC
Single-chip 16-bit/32-bit MCU
DD(3V3)
LPC2361/62
) pins, while the
© NXP B.V. 2008. All rights reserved.
DD(3V3)
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) and