LPC2158 NXP Semiconductors, LPC2158 Datasheet - Page 22

• Manufacturer Part Number: LPC2158
• Description: Single-chip 16-bit/32-bit microcontrollers; 512 kB fash
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC2157_2158_2
Product data sheet
6.16.1 Features
6.17.1 Features
6.16 Watchdog timer
6.17 Real-time clock
6.18 Pulse width modulator
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 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).
The PWM is based on the standard timer block and inherits all of its features, although
only the PWM function is pinned out on the LPC2157/2158. The timer is designed to count
cycles of the peripheral clock (PCLK) and optionally generate interrupts or perform other
actions when specified timer values occur, based on seven match registers. The PWM
function is also based on match register events.
The ability to separately control rising and falling edge locations allows the PWM to be
used for more applications. For instance, multi-phase motor control typically requires three
non-overlapping PWM outputs with individual control of all three pulse widths and
positions.
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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 prescaler.
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.
Dedicated power supply pin can be connected to a battery or the main 3.3 V.
cy(PCLK)
4.
Rev. 02 — 9 February 2009
cy(PCLK)
256
Single-chip 16-bit/32-bit microcontrollers
4) to (T
cy(PCLK)
LPC2157/2158
2
32
© NXP B.V. 2009. All rights reserved.
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4) in multiples of
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