Philips Semiconductors

User’s Manual - Preliminary -

 

 

 

 

 

 

ADDITIONAL FEATURES

P89LPC901/902/903

 

 

13. ADDITIONAL FEATURES

 

 

The AUXR1 register contains several special purpose control bits that relate to several chip features. AUXR1 is described in Figure 13-1.

AUXR1

 

7

6

5

 

4

 

3

 

2

1

0

 

Address: A2h

 

 

CLKLP

EBRR

-

 

-

 

SRST

 

0

-

DPS

 

Not bit addressable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset Source(s): Any reset

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset Value: 000000x0B

 

 

 

 

 

 

 

 

 

 

 

 

 

BIT

SYMBOL

FUNCTION

 

 

 

 

 

 

 

 

 

 

 

AUXR1.7

CLKLP

Clock Low Power Select. When set, reduces power consumption in the clock circuits. Can

 

 

be used when the clock frequency is 8MHz or less. After reset this bit is cleared to support

 

 

up to 12MHz operation (P89LPC901).

 

 

 

 

 

 

AUXR1.6

EBRR

UART Break Detect Reset Enable. If ’1’, UART Break Detect will cause a chip reset

 

 

(P89LPC903). When writing to this register on the P89LPC901 or P89LPC902 devices,

 

 

this bit position should be written with a zero.

 

 

 

 

 

 

AUXR1.5

-

Reserved

 

 

 

 

 

 

 

 

 

 

 

AUXR1.4

-

Reserved

 

 

 

 

 

 

 

 

 

 

 

AUXR1.3

SRST

Software Reset. When set by software, resets the P89LPC901/902/903 as if a hardware

 

 

reset occurred.

 

 

 

 

 

 

 

 

 

 

AUXR1.2

0

This bit contains a hard-wired 0. Allows toggling of the DPS bit by incrementing AUXR1,

 

 

without interfering with other bits in the register.

 

 

 

 

AUXR1.1

-

Not used. Allowable to set to a "1" .

 

 

 

 

 

 

 

 

AUXR1.0

DPS

Data Pointer Select. Chooses one of two Data Pointers.

 

 

 

 

Figure 13-1: AUXR1 Register

Software Reset

The SRST bit in AUXR1 gives software the opportunity to reset the processor completely, as if an external reset or watchdog reset had occurred. If a value is written to AUXR1 that contains a 1 at bit position 3, all SFRs will be initialized and execution will resume at program address 0000. Care should be taken when writing to AUXR1 to avoid accidental software resets.

Dual Data Pointers

The dual Data Pointers (DPTR) adds to the ways in which the processor can specify the address used with certain instructions. The DPS bit in the AUXR1 register selects one of the two Data Pointers. The DPTR that is not currently selected is not accessible to software unless the DPS bit is toggled.

Specific instructions affected by the Data Pointer selection are:

•

INC

DPTR

Increments the Data Pointer by 1.

•

JMP

@A+DPTR

Jump indirect relative to DPTR value.

2003 Dec 8

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Philips P89LPC903, P89LPC901, P89LPC902 user manual Software Reset, Dual Data Pointers, AUXR1
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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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