LPC11C12FBD48 NXP Semiconductors, LPC11C12FBD48 Datasheet - Page 23

• Manufacturer Part Number: LPC11C12FBD48
• Description: The LPC11C12FBD48 is an ARM Cortex-M0 microcontroller designed for 8/16-bit microcontroller applications, offering performance, low power, simple instruction set and memory addressing together with reduced code size compared to existing 8/16-bit arch
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC11CX2_CX4
Product data sheet
Fig 5.
watchdog oscillator
system oscillator
IRC oscillator
IRC oscillator
LPC11Cx2/Cx4 clock generation block diagram
(system PLL clock select)
7.16.1.1 Internal RC oscillator
7.16.1.2 System oscillator
SYSPLLCLKSEL
The IRC may be used as the clock source for the WDT, and/or as the clock that drives the
PLL and subsequently the CPU. The nominal IRC frequency is 12 MHz. The IRC is
trimmed to 1 % accuracy over the entire voltage and temperature range.
Upon power-up or any chip reset, the LPC11Cx2/Cx4 use the IRC as the clock source.
Software may later switch to one of the other available clock sources.
The system oscillator can be used as the clock source for the CPU, with or without using
the PLL.
The system oscillator operates at frequencies of 1 MHz to 25 MHz. This frequency can be
boosted to a higher frequency, up to the maximum CPU operating frequency, by the
system PLL.
SYSTEM PLL
(main clock select)
MAINCLKSEL
All information provided in this document is subject to legal disclaimers.
main clock
Rev. 3 — 27 June 2011
watchdog oscillator
watchdog oscillator
system oscillator
SYSTEM CLOCK
IRC oscillator
IRC oscillator
DIVIDER
(WDT clock update enable)
(CLKOUT update enable)
CLKOUTUEN
WDTUEN
system clock
32-bit ARM Cortex-M0 microcontroller
SYSAHBCLKCTRL[1:18]
(AHB clock enable)
CLKOUT PIN CLOCK
UART PERIPHERAL
LPC11Cx2/Cx4
SPI0 PERIPHERAL
SPI1 PERIPHERAL
CLOCK DIVIDER
CLOCK DIVIDER
CLOCK DIVIDER
18
WDT CLOCK
DIVIDER
DIVIDER
© NXP B.V. 2011. All rights reserved.
AHB clocks 1 to 18
(memories
and peripherals)
AHB clock 0
(system)
SPI0
UART
SPI1
WDT
CLKOUT pin
002aae514
23 of 62