Datasheet

LPC82x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 1 — 1 October 2014 24 of 81
NXP Semiconductors
LPC82x
32-bit ARM Cortex-M0+ microcontroller
8.22 Clocking and power control
8.22.1 Crystal and internal oscillators
The LPC82x include four independent oscillators:
1. The crystal oscillator (SysOsc) operating at frequencies between 1 MHz and 25 MHz.
2. The internal RC Oscillator (IRC) with a fixed frequency of 12 MHz.
3. The internal low-power, low-frequency Oscillator with a nominal frequency of 10 kHz
with 40% accuracy for use with the self-wake-up timer.
4. The dedicated Watchdog Oscillator (WDOsc) with a programmable nominal
frequency between 9.4 kHz and 2.3 MHz with 40% accuracy.
Fig 9. LPC82x clock generation
SYSTEM PLL
watchdog oscillator
IRC oscillator
IRC oscillator
watchdog oscillator
SYSTEM
OSCILLATOR
MAINCLKSEL
(main clock select)
SYSPLLCLKSEL
system PLL clock select
CLOCK DIVIDER
SYSAHBCLKDIV
AHB clock 0
(core, system;
always-on)
CLOCK DIVIDER
UARTCLKDIV
USART0
USART1
USART2
WWDT
IRC oscillator
WKT
low-power oscillator
WKT
watchdog oscillator
IRC oscillator
system oscillator
CLOCK DIVIDER
CLKOUTDIV
CLKOUT pin
CLKOUTSEL
(CLKOUT clock select)
main clock system clock
SYSAHBCLKCTRL[1:29]
(system clock enable)
memories
and peripherals,
peripheral clocks
29
aaa-012136
IOCONCLKDIV
CLOCK DIVIDER
IOCON
glitch filter
7
XTALIN
CLKIN
XTALOUT
SYSCON
PMU
FRACTIONAL RATE
GENERATOR