LPC2131 Philips Semiconductors (Acquired by NXP), LPC2131 Datasheet - Page 20

• Manufacturer Part Number: LPC2131
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
9397 750 14008
Preliminary data sheet
6.18.1 Features
6.19.1 Features
6.18 Watchdog timer
6.19 Real-time clock
The purpose of the watchdog is to reset the microcontroller within a reasonable amount of
time if it enters an erroneous state. When enabled, the watchdog will generate a system
reset if the user program fails to ‘feed’ (or reload) the watchdog within a predetermined
amount of time.
The Real-Time Clock (RTC) is designed to provide a set of counters to measure time
when normal or idle operating mode is selected. The RTC has been designed to use little
power, making it suitable for battery powered systems where the CPU is not running
continuously (Idle mode).
•
•
•
•
•
•
•
•
•
•
•
•
•
Four 32-bit match registers that allow:
– Continuous operation with optional interrupt generation on match.
– Stop timer on match with optional interrupt generation.
– Reset timer on match with optional interrupt generation.
Four external outputs per timer corresponding to match registers, with the following
capabilities:
– Set LOW on match.
– Set HIGH on match.
– Toggle on match.
– Do nothing on match.
Internally resets chip if not periodically reloaded.
Debug mode.
Enabled by software but requires a hardware reset or a watchdog reset/interrupt to be
disabled.
Incorrect/Incomplete feed sequence causes reset/interrupt if enabled.
Flag to indicate watchdog reset.
Programmable 32-bit timer with internal pre-scaler.
Selectable time period from (T
T
Measures the passage of time to maintain a calendar and clock.
Ultra-low power design to support battery powered systems.
Provides Seconds, Minutes, Hours, Day of Month, Month, Year, Day of Week, and Day
of Year.
Can use either the RTC dedicated 32 kHz oscillator input or clock derived from the
external crystal/oscillator input at XTAL1. Programmable Reference Clock Divider
allows fine adjustment of the RTC.
PCLK
4.
Rev. 01 — 18 November 2004
PCLK
256
LPC2131/2132/2138
4) to (T
Single-chip 16/32-bit microcontrollers
PCLK
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
2
32
4) in multiples of
20 of 36