Philips Semiconductors

User’s Manual - Preliminary -

 

 

 

 

 

 

UART (P89LPC903)

P89LPC901/902/903

 

 

SFR Space

 

 

The UART SFRs are at the following locations:

Table 8-1: SFR Locations for UARTs

Register

Description

SFR Location

 

 

 

PCON

Power Control

87H

 

 

 

SCON

Serial Port (UART) Control

98H

 

 

 

SBUF

Serial Port (UART) Data Buffer

99H

 

 

 

SADDR

Serial Port (UART) Address

A9H

 

 

 

SADEN

Serial Port (UART) Address Enable

B9H

 

 

 

SSTAT

Serial Port (UART) Status

BAH

 

 

 

BRGR1

Baud Rate Generator Rate High Byte

BFH

 

 

 

BRGR0

Baud Rate Generator Rate Low Byte

BEH

 

 

 

BRGCON

Baud Rate Generator Control

BDH

 

 

 

Baud Rate Generator and Selection

The P89LPC903 enhanced UART has an independent Baud Rate Generator. The baud rate is determined by a value programmed into the BRGR1 and BRGR0 SFRs. The UART can use either Timer 1 or the baud rate generator output as determined by BRGCON.2-1 (see Figure 8-2). Note that Timer T1 is further divided by 2 if the SMOD1 bit (PCON.7) is cleared. The independent Baud Rate Generator uses CCLK.

Updating the BRGR1 and BRGR0 SFRs

The baud rate SFRs, BRGR1 and BRGR0 must only be loaded when the Baud Rate Generator is disabled (the BRGEN bit in the BRGCON register is ’0’). This avoids the loading of an interim value to the baud rate generator. (CAUTION: If either BRGR0 or BRGR1 is written when BRGEN = 1, the result is unpredictable.)

Table 8-2: Baud Rate Generation for UART

SCON.7

SCON.6

PCON.7

BRGCON.1

Receive/Transmit Baud Rate for UART

(SM0)

(SM1)

(SMOD1)

(SBRGS)

 

 

 

 

 

 

0

0

X

X

CCLK/16

 

 

 

 

 

 

 

0

0

CCLK/(256-TH1)64

 

 

 

 

 

0

1

1

0

CCLK/(256-TH1)32

 

 

 

 

 

 

 

X

1

CCLK/((BRGR1,BRGR0)+16)

 

 

 

 

 

1

0

0

X

CCLK/32

 

 

 

1

X

CCLK/16

 

 

 

 

 

 

 

 

 

0

0

CCLK/(256-TH1)64

 

 

 

 

 

1

1

1

0

CCLK/(256-TH1)32

 

 

 

 

 

 

 

X

1

CCLK/((BRGR1,BRGR0)+16)

 

 

 

 

 

2003 Dec 8

62

Page 62
Image 62
Philips P89LPC902 P89LPC901/902/903 SFR Space, Baud Rate Generator and Selection, Updating the BRGR1 and BRGR0 SFRs

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.