Register Description; Crystal Oscillator - Philips LPC2101 User Manual

Philips Semiconductors
Volume 1

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.
Table 6:
Name
External Interrupts
EXTINT
INTWAKE
EXTMODE
EXTPOLAR
Memory Mapping Control
MEMMAP
Phase Locked Loop
PLLCON
PLLCFG
PLLSTAT
PLLFEED
Power Control
PCON
PCONP
APB Divider
APBDIV
Reset
RSIR
Code Security/Debugging
CSPR
Syscon Miscellaneous Registers
SCS
[1]

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
referred to as CCLK for purposes of rate equations, etc. elsewhere in this document. F
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
The onboard oscillator in the LPC2101/02/03 can operate in one of two modes: slave
mode and oscillation mode.
User manual
Summary of system control registers
Description
External Interrupt Flag Register
Interrupt Wake-up Register
External Interrupt Mode Register
External Interrupt Polarity Register
Memory Mapping Control
PLL Control Register
PLL Configuration Register
PLL Status Register
PLL Feed Register
Power Control Register
Power Control for Peripherals
APB Divider Control
Reset Source Identification Register
Code Security Protection Register
System Controls and Status
Reset value reflects the data stored in used bits only. It does not include reserved bits content.
Rev. 01 — 12 January 2006
Chapter 3: System control block
Access Reset
value
R/W 0
R/W 0
R/W 0
R/W 0
R/W 0
R/W 0
R/W 0
RO 0
WO NA
R/W 0
R/W 0x03BE
R/W 0
R/W 0
RO 0
R/W 0
and the ARM processor clock frequency is
OSC
for details and frequency limitations.
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
UM10161
Address
[1]
0xE01F C140
0xE01F C144
0xE01F C148
0xE01F C14C
0xE01F C040
0xE01F C080
0xE01F C084
0xE01F C088
0xE01F C08C
0xE01F C0C0
0xE01F C0C4
0xE01F C100
0xE01F C180
0xE01F C184
0xE01F C1A0
OSC
16