LH79520 データシートの表示（PDF） - NXP Semiconductors.

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LH79520

System-on-Chip

NXP Semiconductors. 

LH79520

NXP Semiconductors

System-on-Chip

Reset, Clock, and Power

Controller (RCPC)

The RCPC generates the various clock signals for the

operation of the LH79520 and provides for an orderly

start-up after power-on and during a wake-up from one

of the power saving operating modes. The RCPC allows

the software to individually select the frequency of the

various on-chip clock signals as required to operate the

chip in the most power-efficient mode. It features:

• 14.7456 MHz crystal oscillator and PLL for on-chip

Clock generation

• External Clock input if on-chip oscillator and PLL are

not used

• 32.768 kHz crystal oscillator generating 1 Hz clock

for Real Time Clock

• Individually controlled clocks for peripherals and CPU

• Clock source for UARTs is selectable between

14.7456 MHz crystal oscillator and external clock

source

• Programmable clock prescalers for UARTs and

PWMs

• Five global power control modes are available:

– Active

– Standby

– Sleep

– Stop1

– Stop2

• CPU and Bus clock frequency can be changed

on the fly

• Selectable clock output

• Hardware reset (nRESETIN) and software reset.

The 32.768 kHz crystal oscillator is not required for

chip operation, so it may be left out of the design to

save power. If this crystal is not used, XTALIN should

be pulled to VDD or VSS so the input does not float.

Table 7. Clock and Enable States for Different Power Modes

(Using On-chip Oscillator and PLL)

FUNCTION

14.7456 MHz Oscillator

PLL

Peripheral Clock

CPU Clock

ACTIVE STANDBY SLEEP STOP1 STOP2

ON

ON

ON

ON

OFF

ON

ON

ON

OFF OFF

ON

ON

OFF OFF OFF

ON

OFF

OFF OFF OFF

20

Rev. 01 — 16 July 2007

Preliminary data sheet

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