UM10429
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2010. All rights reserved.
User manual
Rev. 1 — 20 October 2010
10 of 258
NXP Semiconductors
UM10429
Chapter 3: LPC1102 System configuration
3.5 Register description
All registers, regardless of size, are on word address boundaries. Details of the registers
appear in the description of each function.
See
for the flash access timing register, which can be re-configured as part
the system setup. This register is not part of the system configuration block.
Fig 3.
LPC1102 CGU block diagram
SYSTEM PLL
IRC oscillator
system oscillator
watchdog oscillator
IRC oscillator
watchdog oscillator
MAINCLKSEL
(main clock select)
SYSPLLCLKSEL
(system PLL clock select)
SYSTEM CLOCK
DIVIDER
AHB clock 0
(system)
AHBCLKCTRL[1:18]
SPI0 PERIPHERAL
CLOCK DIVIDER
SPI0_PCLK
UART PERIPHERAL
CLOCK DIVIDER
UART_PCLK
WDT CLOCK
DIVIDER
WDT_PCLK
WDTUEN
(WDT clock update enable)
main clock
system clock
IRC oscillator
AHB clocks
1 to 18
(memories
and peripherals)
18
sys_pllclkout
sys_pllclkin
Table 5.
Register overview: system control block (base address 0x4004 8000)
Name
Access
Address offset Description
Reset
value
Reference
SYSMEMREMAP
R/W
0x000
System memory remap
0x002
PRESETCTRL
R/W
0x004
Peripheral reset control
0x000
SYSPLLCTRL
R/W
0x008
System PLL control
0x000
SYSPLLSTAT
R
0x00C
System PLL status
0x000
-
-
0x010 - 0x01C
Reserved
-
-
SYSOSCCTRL
R/W 0x020
System
oscillator
control
0x000
WDTOSCCTRL
R/W 0x024
Watchdog
oscillator
control
0x000
IRCCTRL
R/W
0x028
IRC control
0x080
-
-
0x02C
Reserved
-
-