lpc1778 NXP Semiconductors, lpc1778 Datasheet - Page 63

• Manufacturer Part Number: lpc1778
• Description: 32-bit Arm Cortex-m3 Microcontroller; Up To 512 Kb Flash And 96 Kb Sram; Usb Device/host/otg; Ethernet; Lcd; Emc
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC178x_7x
Objective data sheet
7.32.1 Crystal oscillators
7.32 Clocking and power control
The LPC178x/7x include three independent oscillators. These are the main oscillator, the
IRC oscillator, and the RTC oscillator. Each oscillator can be used for more than one
purpose as required in a particular application. Any of the three clock sources can be
chosen by software to drive the main PLL and ultimately the CPU.
Following reset, the LPC178x/7x will operate from the Internal RC oscillator until switched
by software. This allows systems to operate without any external crystal and the boot
loader code to operate at a known frequency.
See
•
•
Backup registers (20 bytes) powered by VBAT.
RTC power supply is isolated from the rest of the chip.
Figure 7
for an overview of the LPC178x/7x clock generation.
All information provided in this document is subject to legal disclaimers.
Rev. 00.04 — 8 July 2010
32-bit ARM Cortex-M3 microcontroller
LPC178x/7x
© NXP B.V. 2010. All rights reserved.
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