© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
User manual
Rev. 01 — 12 January 2006
16
Philips Semiconductors
UM10161
Volume 1
Chapter 3: System control block
3.3 Register description
All registers, regardless of size, are on word address boundaries. Details of the registers
appear in the description of each function.
[1]
Reset value reflects the data stored in used bits only. It does not include reserved bits content.
3.4 Crystal oscillator
The LPC2101/02/03 onboard oscillator circuit supports external crystals in the range of
1 MHz to 25 MHz only. If the on-chip PLL system or the boot-loader is used, the input
clock frequency is limited to an exclusive range of 10 MHz to 25 MHz.
The oscillator output frequency is called F
OSC
and the ARM processor clock frequency is
referred to as CCLK for purposes of rate equations, etc. elsewhere in this document. F
OSC
and CCLK are the same value unless the PLL is running and connected. Refer to the
Section 3.8 “Phase Locked Loop (PLL)” on page 24
for details and frequency limitations.
The onboard oscillator in the LPC2101/02/03 can operate in one of two modes: slave
mode and oscillation mode.
Table 6:
Summary of system control registers
Name
Description
Access
Reset
value
Address
External Interrupts
EXTINT
External Interrupt Flag Register
R/W
0
0xE01F C140
INTWAKE
Interrupt Wake-up Register
R/W
0
0xE01F C144
EXTMODE
External Interrupt Mode Register
R/W
0
0xE01F C148
EXTPOLAR
External Interrupt Polarity Register
R/W
0
0xE01F C14C
Memory Mapping Control
MEMMAP
Memory Mapping Control
R/W
0
0xE01F C040
Phase Locked Loop
PLLCON
PLL Control Register
R/W
0
0xE01F C080
PLLCFG
PLL Configuration Register
R/W
0
0xE01F C084
PLLSTAT
PLL Status Register
RO
0
0xE01F C088
PLLFEED
PLL Feed Register
WO
NA
0xE01F C08C
Power Control
PCON
Power Control Register
R/W
0
0xE01F C0C0
PCONP
Power Control for Peripherals
R/W
0x03BE
0xE01F C0C4
APB Divider
APBDIV
APB Divider Control
R/W
0
0xE01F C100
Reset
RSIR
Reset Source Identification Register
R/W
0
0xE01F C180
Code Security/Debugging
CSPR
Code Security Protection Register
RO
0
0xE01F C184
Syscon Miscellaneous Registers
SCS
System Controls and Status
R/W
0
0xE01F C1A0