UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 42 of 792
NXP Semiconductors UM10237
Chapter 4: LPC24XX Clocking and power control
Fig 12. Clock generation for the LPC2400
MAIN
OSCILLATOR
INTERNAL
RC
OSCILLATOR
RTC
OSCILLATOR
PLL
WATCHDOG
TIMER
RTC
PRESCALER
REAL-TIME
CLOCK
BYPASS
SYNCHRO-
NIZER
CPU
CLOCK
DIVIDER
PERIPHERAL
CLOCK
GENERATOR
USB BLOCK

ARM7

TDMI-S

ETHERNET
BLOCK
EMC, LCD,
DMA, FAST I/O
VIC
EXTERNAL
ETHERNET
PHY
2 kB BATTERY
RAM
USB
CLOCK
DIVIDER
system
clock
select
(CLKSRCSEL)
WDT
clock
select
(WDTCLKSEL)
RTC
clock
select
(CCR)
USB clock config
(USBCLKCFG)
CPU clock config
(CCLKCFG)
pllclk
CCLK/8
CCLK/6
CCLK/4
CCLK/2
CCLK
PCLK
SEL0[27:26]
PCLK
SEL0[1:0]
PCONP[13]
PCLK
SEL0[19:18]
PCONP[9]
pclkWDT
pclkCAN1
pclkMCI
pclkSYSCON
pclkRTC
PCLK
SEL1[1:0]
pclkBAT_RAM
rtclk
CAN1
PCLK
SEL1[25:24]
PCONP[28]
MCI
PCLK
SEL1[29:28]
SYSTEM
CTRL
other peripherals
see PCLKSEL0/1
25 or
50 MHz
usbclk
(48 MHz)
cclk