Philips Semiconductors

 

 

User’s Manual - Preliminary -

 

 

 

 

 

 

 

WATCHDOG TIMER

 

P89LPC901/902/903

 

Table 12-2: P89LPC901/902/903 Watchdog Timeout Values

 

 

 

 

Timeout Period

Watchdog Clock Source

 

 

 

 

 

 

PRE2-PRE0

WDL in decimal)

(in watchdog clock

 

 

 

400KHz Watchdog Oscillator Clock

12MHz CCLK (6MHz CCLK/2

 

 

 

cycles)

 

 

 

(Nominal)

Watchdog Clock)

 

 

 

 

 

 

 

 

 

 

 

000

0

33

82.5µs

5.50µs

 

 

 

 

 

 

255

8,193

20.5ms

1.37ms

 

 

 

 

 

 

 

 

 

001

0

65

162.5µs

10.8µs

 

 

 

 

 

 

255

16,385

41.0ms

2.73ms

 

 

 

 

 

 

 

 

 

010

0

129

322.5µs

21.5µs

 

 

 

 

 

 

255

32,769

81.9ms

5.46ms

 

 

 

 

 

 

 

 

 

011

0

257

642.5µs

42.8µs

 

 

 

 

 

 

255

65,537

163.8ms

10.9ms

 

 

 

 

 

 

 

 

 

100

0

513

.1.28ms

85.5µs

 

 

 

 

 

 

255

131,073

327.7ms

21.8ms

 

 

 

 

 

 

 

 

 

101

0

1,025

2.56ms

170.8µs

 

 

 

 

 

 

255

262,145

655.4ms

43.7ms

 

 

 

 

 

 

 

 

 

110

0

2,049

5.12ms

341.5µs

 

 

 

 

 

 

255

524,289

1.31s

87.4ms

 

 

 

 

 

 

 

 

 

111

0

4097

10.2ms

682.8µs

 

 

 

 

 

 

255

1,048,577

2.62s

174.8ms

 

 

 

 

 

 

 

 

 

 

 

 

 

WDL (C1H)

 

 

MOV WFEED1, #0A5H

 

 

 

 

 

 

 

MOV WFEED2, #05AH

 

 

 

 

 

 

 

Watchdog

 

 

 

 

8-Bit Down

 

 

 

Oscillator

÷32

PRESCALER

 

 

 

RESET

PCLK

 

 

 

 

Counter

 

Watchdog reset can also be caused

 

 

 

 

 

 

 

by an invalid feed sequence, or by

 

 

 

 

 

 

 

writing to WDCON not immediately

 

 

 

 

 

 

 

followed by a feed sequence

 

 

 

 

control register

 

 

 

SHADOW

 

 

 

 

 

 

 

REGISTER FOR

 

 

 

 

 

 

 

 

WDCON

 

 

PRE2

PRE1

PRE0

WDRUN

WDTOF

WDCLK

WDCON(A7H)

 

 

 

 

 

 

 

 

Figure 12-3: Watchdog Timer in Watchdog Mode (WDTE = 1)

2003 Dec 8

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Philips P89LPC902, P89LPC903 user manual P89LPC901/902/903 Watchdog Timeout Values, Prescaler Reset Pclk, WDCONA7H

P89LPC903, P89LPC902, P89LPC901 specifications

The Philips P89LPC901, P89LPC902, and P89LPC903 are a series of 8-bit microcontrollers designed for embedded system applications. These models, which belong to the LPC900 series, are notable for their affordability and versatility, making them an attractive choice for both hobbyists and professional developers.

One of the core features of the P89LPC901, P89LPC902, and P89LPC903 microcontrollers is their powerful 8-bit architecture. Operating at clock speeds up to 20 MHz, they deliver efficient performance suited for a range of tasks. Each model includes a comprehensive instruction set that supports various data manipulation and arithmetic functions, enabling extensive programming capabilities.

These microcontrollers come with built-in memory, with configurations that vary among the three models. The P89LPC901 typically features 4 KB of Flash memory and 256 bytes of RAM, while the P89LPC902 and P89LPC903 offer enhanced memory options. This Flash memory allows for reprogrammability, making it easier to update and modify applications as needed.

Another significant characteristic of the LPC900 series is their integrated peripherals. These models are equipped with a variety of I/O ports, allowing for easy interfacing with other devices and components. The P89LPC901 supports up to 32 I/O pins, while the P89LPC902 and P89LPC903 provide additional features such as analog-to-digital converters (ADCs), timers, and serial communication interfaces. This broad range of peripherals empowers developers to design complex applications without needing extra hardware.

Power consumption is also a key consideration for microcontroller applications. The P89LPC901, P89LPC902, and P89LPC903 are designed with low power consumption in mind, making them ideal for battery-operated devices and energy-efficient projects. They can operate in various power modes, allowing for greater flexibility in deployment.

In terms of technology, these microcontrollers utilize advanced CMOS technology, ensuring high reliability and durability. Their design offers a robust solution for numerous applications, including consumer electronics, industrial controls, and automation systems.

In summary, the Philips P89LPC901, P89LPC902, and P89LPC903 microcontrollers present an attractive combination of performance, integrated peripherals, low power consumption, and versatility. Their features cater to a wide array of applications, keeping them relevant in a rapidly evolving technology landscape. For hobbyists and professionals alike, these microcontrollers represent a reliable foundation for embedded system development.