UM10429
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© NXP B.V. 2010. All rights reserved.
User manual
Rev. 1 — 20 October 2010
9 of 258
3.1 How to read this chapter
This chapter applies to part LPC1102.
3.2 Introduction
The system configuration block controls oscillators, start logic, and clock generation of the
LPC1102. Also included in this block are registers for setting the priority for AHB access
and a register for remapping flash, SRAM, and ROM memory areas.
3.3 Pin description
shows pins that are associated with system control block functions.
3.4 Clocking and power control
See
for an overview of the LPC1102 Clock Generation Unit (CGU).
The LPC1102 include three independent oscillators. These are the system oscillator, the
Internal RC oscillator (IRC), and the watchdog oscillator. Each oscillator can be used for
more than one purpose as required in a particular application.
Following reset, the LPC1102 will operate from the Internal RC oscillator until switched by
software. This allows systems to operate without any external crystal and the bootloader
code to operate at a known frequency.
The SYSAHBCLKCTRL register gates the system clock to the various peripherals and
memories. UART, the WDT, and SPI0 have individual clock dividers to derive peripheral
clocks from the main clock.
For details on power control see
.
UM10429
Chapter 3: LPC1102 System configuration
Rev. 1 — 20 October 2010
User manual
Table 4.
Pin summary
Pin name
Pin direction
Pin description
PIO0_0; PIO0_8 to PIO0_11
I
Start logic wake-up pins port 0
PIO1_0
I
Start logic wake-up pin port 1