Philips Semiconductors

User’s Manual - Preliminary -

 

 

 

 

 

 

CLOCKS

P89LPC901/902/903

 

If CCLK is 8MHz or slower, the CLKLP SFR bit (AUXR1.7) can be set to ’1’ to reduce power consumption. On reset, CLKLP is ’0’ allowing highest performance access. This bit can then be set in software if CCLK is running at 8MHz or slower.

TRIM

 

7

6

5

4

3

2

1

0

 

Address: 96h

 

 

 

 

-

ENCLK

TRIM.5

TRIM.4

TRIM.3

TRIM.2

TRIM.1

TRIM.0

 

Not bit addressable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset Source(s): Power-up only

 

 

 

 

 

 

 

 

 

 

Reset Value: On power-up reset, ENCLK = 0, and TRIM.5-0 are loaded with the factory programmed value.

 

 

BIT

SYMBOL

FUNCTION

 

 

 

 

 

 

 

 

TRIM.7

-

Reserved.

 

 

 

 

 

 

 

 

TRIM.6

ENCLK

When ENCLK =1, CCLK/ 2 is output on the XTAL2 pin (P3.0) provided that the crystal

 

 

oscillator is not being used. When ENCLK=0, no clock output is enabled.(P89LPC901).

TRIM.5-0

 

Trim value.

 

 

 

 

 

 

 

 

Note: on reset, the TRIM SFR is initialized with a factory preprogrammed value. When setting or clearing either the ENCLK or RCCLK bits, the user should retain the contents of bits 5:0 of the TRIM register. This can be done by reading the contents of the TRIM register (into the ACC for example), modifying bits 6 or 7, and writing this result back into the TRIM register.

Alternatively, the "ANL direct" or "ORL direct" instructions can be used to clear or set bit 6 or 7of the TRIM register.

Figure 2-2: On-Chip RC Oscillator TRIM Register

Watchdog Oscillator Option

The watchdog has a separate oscillator which has a nominal frequency of 400KHz. This oscillator can be used to save power when a high clock frequency is not needed.

External Clock Input Option - P89LPC901

In this configuration, the processor clock is derived from an external source driving the XTAL1 / P3.1 pin. The rate may be from 0 Hz up to 12 MHz. The XTAL2 / P3.0 pin may be used as a standard port pin or a clock output.

2003 Dec 8

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Philips P89LPC902, P89LPC903 Watchdog Oscillator Option, External Clock Input Option P89LPC901, Trim, BIT Symbol Function
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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.
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