LH79520_N NXP Semiconductors, LH79520_N Datasheet - Page 20

• Manufacturer Part Number: LH79520_N
• Description: The LH79520, powered by an ARM720T, is a completeSystem-on-Chip with a high level of integration tosatisfy a wide range of requirements and expectations
• Manufacturer: NXP Semiconductors

LH79520
Reset, Clock, and Power
Controller (RCPC)
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
• External Clock input if on-chip oscillator and PLL are
• 32.768 kHz crystal oscillator generating 1 Hz clock
• Individually controlled clocks for peripherals and CPU
• Clock source for UARTs is selectable between
20
Clock generation
not used
for Real Time Clock
14.7456 MHz crystal oscillator and external clock
source
The RCPC generates the various clock signals for the
14.7456 MHz Oscillator
PLL
Peripheral Clock
CPU Clock
FUNCTION
Table 7. Clock and Enable States for Different Power Modes
(Using On-chip Oscillator and PLL)
Rev. 01 — 16 July 2007
ACTIVE
NXP Semiconductors
ON
ON
ON
ON
STANDBY
OFF
ON
ON
ON
• Programmable clock prescalers for UARTs and
• Five global power control modes are available:
• CPU and Bus clock frequency can be changed
• Selectable clock output
• Hardware reset (nRESETIN) and software reset.
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.
PWMs
on the fly
– Active
– Standby
– Sleep
– Stop1
– Stop2
The 32.768 kHz crystal oscillator is not required for
SLEEP
OFF
OFF
ON
ON
STOP1
OFF
OFF
OFF
ON
STOP2
Preliminary data sheet
OFF
OFF
OFF
OFF
System-on-Chip