LPC2101_02_03_1

© Koninklijke Philips Electronics N.V. 2006. All rights reserved.

Preliminary data sheet

Rev. 01 — 18 January 2006

19 of 32

Philips Semiconductors

LPC2101/2102/2103

Single-chip 16-bit/32-bit microcontrollers

6.17.7 Power control

The LPC2101/2102/2103 supports two reduced power modes: Idle mode and

Power-down mode.

In Idle mode, execution of instructions is suspended until either a reset or interrupt occurs.

Peripheral functions continue operation during Idle mode and may generate interrupts to

cause the processor to resume execution. Idle mode eliminates power used by the

processor itself, memory systems and related controllers, and internal buses.

In Power-down mode, the oscillator is shut down and the chip receives no internal clocks.

The processor state and registers, peripheral registers, and internal SRAM values are

preserved throughout Power-down mode and the logic levels of chip output pins remain

static. The Power-down mode can be terminated and normal operation resumed by either

a reset or certain specific interrupts that are able to function without clocks. Since all

dynamic operation of the chip is suspended, Power-down mode reduces chip power

consumption to nearly zero.

Selecting an external 32 kHz clock instead of the PCLK as a clock-source for the on-chip

RTC will enable the microcontroller to have the RTC active during Power-down mode.

Power-down current is increased with RTC active. However, it is significantly lower than in

Idle mode.

A Power Control for Peripherals feature allows individual peripherals to be turned off if

they are not needed in the application, resulting in additional power savings during active

and Idle mode.

6.17.8 APB bus

The APB divider determines the relationship between the processor clock (CCLK) and the

clock used by peripheral devices (PCLK). The APB divider serves two purposes. The first

is to provide peripherals with the desired PCLK via APB bus so that they can operate at

the speed chosen for the ARM processor. In order to achieve this, the APB bus may be

⁄

1

⁄

properly at power-up (and its timing cannot be altered if it does not work since the APB

divider control registers reside on the APB bus), the default condition at reset is for the

⁄

is to allow power savings when an application does not require any peripherals to run at

the full processor rate. Because the APB divider is connected to the PLL output, the PLL

remains active (if it was running) during Idle mode.

6.18 Emulation and debugging

The LPC2101/2102/2103 support emulation and debugging via a JTAG serial port.

6.18.1 EmbeddedICE

Standard ARM EmbeddedICE logic provides on-chip debug support. The debugging of

the target system requires a host computer running the debugger software and an

EmbeddedICE protocol convertor. EmbeddedICE protocol convertor converts the Remote

Debug Protocol commands to the JTAG data needed to access the ARM core.

The ARM core has a Debug Communication Channel function built-in. The debug

communication channel allows a program running on the target to communicate with the

host debugger or another separate host without stopping the program flow or even