Embedded Artists AB LPC2148 User Guide

LPC2148 Education Board - User’s Guide

LPC2148 Education Board

User’s Guide

Learn everything there is about the new ARM7 32-bit MCU’s…

Start Developing Your Applications On Day 1!

EA2-USG-0601 v1.2 Rev B

LPC2148 Education Board - User’s Guide Page 2

Embedded Artists AB

Friisgatan 33 SE-214 21 Malmö Sweden

info@EmbeddedArtists.com http://www.EmbeddedArtists.com

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Table of Contents

1 Introduction 5

1.1 Contents 5

1.2 Features 5

1.3 Expansion Boards 6

1.4 Other Products from Embedded Artists 7

1.4.1 Design and Production Services 7

1.4.2 LPC2xxx QuickStart Boards and Kits 7

2 Board Design 8

2.1 Board Schematics 8

2.1.1 Page 1: CPU 11

2.1.2 Page 1: Power Supply 12

2.1.3 Page 1: RS232 and ISP 12

2.1.4 Page 1: USB 13

2.1.5 Page 1: JTAG 14

2.1.6 Page 1: Expansion Connector 14

2.1.7 Page 2: LEDs 15

2.1.8 Page 2: Push-button 16

2.1.9 Page 2: Joystick-switch 16

2.1.10 Page 2: RGB-LED 17

2.1.11 Page 2: Buzzer 18

2.1.12 Page 2: Servo Motor Interface 19

2.1.13 Page 2: MMC/SD Interface 19

2.1.14 Page 2: Reset Generation and I2C E2PROM 20

2.1.15 Page 3: Analog Inputs 20

2.1.16 Page 3: Analog Outputs 21

2.1.17 Page 3: 2x16 Character LCD 21

2.1.18 Page 3: 8x8 LED Matrix with SPI Interface 22

2.1.19 Page 3: Brushless DC Motor Control 23

2.2 Jumpers 25

2.2.1 Illegal Jumper Combinations 25

2.3 Connectors 26

2.4 Important Components 27

2.5 Mechanical Dimensions 28

2.6 JTAG Interface and Reset Control Issue 28

3 Getting Started 29

3.1 Test program 29

3.2 Program Development 29

4 CD-ROM and Product Registration 30

4.1 CD-ROM 30

4.2 Product Registration 30

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5 Further Information 31

6 App.A – 10M Ethernet Expansion Board 32

6.1 Board Schematics 32

7 App.B – Bluetooth Expansion Board 34

7.1 Board Schematics 34

8 App.C – Graphical LCD Expansion Board 36

8.1 Board Schematics 36

9 App.D – UART & RS485 Expansion Board 38

9.1 Board Schematics 38

10 App.E – MP3 Decoder Expansion Board 40

10.1 Board Schematics 40

11 App.F – ZigBee Expansion Board 42

11.1 Board Schematics 42

12 App.G – Prototype Expansion Board 44

12.1 Board Schematics 44

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1 Introduction

Thank you for buying Embedded Artists’ LPC2148 Education Board based on Philips ARM7TDMI LPC2148 microcontroller.

This document is a User’s Guide that describes the LPC2148 Education Board hardware design and some basic software interface principles with the hardware. There is a separate document describing program development that also includes a lot of experiments that will guide you through the art of embedded program development.

1.1 Contents

The box received when ordering the LPC2148 Education Board contains the following:

• The LPC2148 Education Board.

• A modem serial cable, DB9-male to DB9-female (DB9M-DM9F), for connecting

the LPC2148 Education Board to a PC.

• A USB cable of type: B-to-A, for powering the boards from a PC.

• CD-ROM with additional material and programs, including complete and evaluation

versions of different development environments.

An optional JTAG interface can be used for debugging during program development. The interface is not strictly needed but can be needed for more advanced debugging.

1.2 Features

Embedded Artists LPC2148 Education Board with Philips ARM7TDMI LPC2148 microcontroller lets you get up-and-running quickly. The small form factor board offers many unique features that ease your learning curve and program development.

• Philips ARM7TDMI LPC2148 microcontroller with 512 KByte program Flash and

32+8 KByte SRAM

• 12.0000 MHz crystal for maximum execution speed and standard serial bit rates

− Phase-locked loop (PLL) multiplies frequency with five; 5 x 12 MHz = 60 MHz

• 32.768kHz RTC crystal

• Onboard Peripherals

− 2x16 character LCD with background light

− Joystick switch

− RS232 interface on UART #0

− USB 2.0 device interface

− RGB-LED, each color can be controlled via PWM signal

− 8 LEDs

− Pushbutton on P0.14 (interrupt input)

− 8x8 LED matrix, controlled via shift registers in the SPI bus

− MMC/SD memory card interface

− Brushless DC motor control

− Piezoelectric buzzer

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− Servo interface (3-pole)

− 2 Analog inputs

− Low-pass filtering of PWM signal

− 1 Analog output

− Reset button

• Connectors

− RS232, female DSUB-9 (ESD protected)

− USB, type B connector

− MMC/SD memory card connector

− Servo (3-pin) connector

− JTAG

− 64 pin expansion connector, all LPC2148 I/O pins are available on connector

− 2.1 mm power supply connector

• 2 Kbit I

C E2PROM for storing non-volatile parameters

• Onboard low-dropout voltage and reset generation.

− Generates +3.3V from a +5V supply

− +3.3V available for external circuits, up to 300 mA

• Power supply

− 4.5-6 VDC, ≥150 mA, either from USB connector or 2.1 mm power connector

• Simple and automatic program download (ISP) via RS232 channel

− Circuit that automatically controls the bootloader from RS232 channel

• Dimensions: 139 x 110 mm

− Four layer PCB (FR-4 material) for best noise immunity

1.3 Expansion Boards

The 64 pin expansion connector, with all LPC2148 I/O pins available, allows the LPC2148 Education Board to be expanded with new and exciting hardware. The experiments can be

more advanced and complex by using the expansion boards. The list below presents the first set of available expansion boards. As seen, many of the boards are communication oriented.

• Ethernet board (10Mbps) with SPI interface

• Bluetooth™ board with UART interface

• ZigBee™ board with SPI interface

• MP3 decoder board with SPI interface

• Graphical monochrome LCD (240x128 pixels) with parallel interface

• Modem (UART#1) and RS485 board

• Prototype board

More boards are in preparation, for example:

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• GSM/GPRS modem board

• GPS board

• WLAN (IEEE802.11) board

…and many more to come!

1.4 Other Products from Embedded Artists

Embedded Artists have a broad range of LPC2xxx based boards that are very low cost and developed for prototyping / development as well as for OEM applications. Modifications for OEM applications can be done easily, even for modest production volumes. Contact Embedded Artists for further information about design and production services.

1.4.1 Design and Production Services

Embedded Artists provide design services for custom designs, either completely new or modification to existing boards. Specific peripherals and I/O can be added easily to different designs, for example, communication interfaces, specific analog or digital I/O, and power supplies. Embedded Artists has a broad, and long, experience in designing industrial electronics, in general, and with Philips LPC2xxx microcontroller family, in specific. Our competence also includes wireless and wired communication for embedded systems. For example IEEE802.11b/g (WLAN), Bluetooth™, ZigBee™, ISM RF, Ethernet, CAN, RS485, and Fieldbuses.

1.4.2 LPC2xxx QuickStart Boards and Kits

Visit Embedded Artists’ home page, www.EmbeddedArtists.com, for information about other QuickStart boards / kits or contact your local distributor.

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2 Board Design

This chapter contains detailed information about the electrical and mechanical design of the LPC2148 Education Board.

2.1 Board Schematics

Figure 1 - LPC2148 Education Board Schematic, page 1

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Figure 2 - LPC2148 Education Board Schematic, page 2

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Figure 3 - LPC2148 Education Board Schematic, page 3

The following subsections describe in more detail each part of the design. Each schematic page is described in turn.

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2.1.1 Page 1: CPU

The core part of the design is the Philips LPC2148 microcontroller. It’s an ARM7TDMI-S CPU core with a lot of different peripheral units and on-chip memory (512 kByte FLASH and 32-8 kByte SRAM). There is no external memory bus interface. Figure 4 below illustrates the CPU section of the design.

Figure 4 - LPC2148 Education Board Schematic, page 1: CPU

The microcontroller crystal frequency is 12.0000 MHz. This frequency has been selected in order to allow maximum execution speed (5 x 12 MHz = 60 MHz, which is the maximum frequency). The on-chip UART peripheral includes a fractional baud rate generator that allow standard baud rates to be generated from the 60 MHz base clock. The USB clock is also generated from the 60 MHz clock without any problems.

There is also a 32.768 kHz crystal clock for the on-chip real-time clock peripheral unit or RTC for short. The microcontroller can be placed in a very low power mode while the RTC operates and keeps track of time. Power for the RTC (during these low power modes) comes from the VBAT input pin. Power is sourced either from the +3.3V power supply or the external VBAT_IN signal (available on the expansion connector), depending on which one have highest voltage.

The LPC2148 also contains an Analog-to-Digital Converter or ADC for short, as well as a Digital-to-Analog Converter (DAC). These two peripheral units need a reference voltage, which is supplied from the VREF input pin.

Jumper J6 selects two different sources for VREF. The CPU power supply (+3.3V) is used and divided by 3/2. The power supply is low-pass filtered for noise immunity. The precision of the power supply is 1%. Alternatively an external precision voltage is used, the VREF_IN pin on the expansion connector.

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2.1.2 Page 1: Power Supply

The power supply uses a conventional low-dropout voltage regulator, the Sipex SP1117. The LPC2148 need only a single +3.3V voltage and has an internal 1.8V regulator for powering the core. Some other processors in the LPC2xxx series require both a +3.3V and a +1.8V voltage. For a full specification of the SP1117 voltage regulator see the datasheet from Sipex (also included on the CD-ROM).

Figure 5 below illustrates the voltage regulator part of the design. As seen, power can come from either an external power adapter via a standard 2.1 mm power connector or from the USB connector. Diode D4 keeps the USB interface from being reverse-fed. Normally, power is taken from the USB connector, but in some cases the 2.1 mm connector can be used, for example when the power need for expansion boards is high and the USB cannot supply the needed current (≥500mA).

A transient suppression diode (D5) protects the board from power surges via the power input.

Figure 5 - LPC2148 Education Board Schematic, page 1: Power Supply

There are three pads to ease measurements of the incoming (+5V) voltage and the generated (+3.3V) voltage, see PAD1 – PAD3. When ON, a small green LED indicates the presence of +3.3V voltage. See Figure 26 on page 27 for a description where the pads and the green LED are placed on the PCB.

2.1.3 Page 1: RS232 and ISP

UART#0 on the LPC2148 is connected to a RS232 interface via a Sipex SP3232E standard RS232 interface chip. It’s a 3.3V powered chip with integrated ESD protection in order to minimize the risk of damaging the interface. The RS232 interface is not a full interface, only the receive and transmit signals are connected to UART#0. There are two UART channels on the LPC2148 and only channel #1 has all control signals needed for a full modem implementation. Channel #0 only has receive and transmit signals. Channel #1 is free and used by some of the expansion boards.

Even though the CPU clock crystal is 12.000 MHz, any standard baud rate can be generated since both UART channels have a fractional baud rate generator. ‘Fractional’ means that the clock frequency does not have to be divided by an even integer value. It can also be divided by a fractional value, which means that a lot more baud rates can be achieved from basically any clock crystal frequency. There is even an autobauding capability, meaning that basically any baud rate can be detected. Read more about this functionality in the LPC2148 datasheet.

The interface can be disconnected by removing jumper J3 and J4, in case an external interface is to be designed (for example on a prototype board).

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Finally there is a special circuit to automate the ISP feature (In-System Programming). With the help of two control signals (RTS and DTR), the processor can be placed in the bootloader mode. The bootloader uses UART#0 for downloading new program images into the processor (either into FLASH or into RAM). DTR controls the processor reset and RTS can pull signal P0.14 low. If the processor samples P0.14 low after reset the bootloader is entered, else the application code is executed. The automatic ISP functionality can be disabled by removing jumpers J5 and J7. Note that some terminal programs (notably Windows™ Hyperterminal) control the RTS/DTR signals in an unfavorable way so that the board always enters bootloader mode or is always in reset more. In these cases, the jumpers must be removed or a serial cable with only receive and transmit signals must be used.

Figure 6 below illustrates the RS232 and ISP part of the design.

Figure 6 - LPC2148 Education Board Schematic, page 1: RS232 and ISP

2.1.4 Page 1: USB

The LPC2148 also contains a USB 2.0 device interface as one of its peripheral units. Figure 7 below illustrate the USB part of the design. Low-pass filtering is added for noise

immunity. The USB interface supports the Soft Connect functionality and voltage sense (see LPC2148 User’s Manual for more information about these functions). The Soft Connect feature is controlled by IO-pin P0.31 and is activated by placing a 1.5 kohm resistor between the D+ signal and +3.3V. A green LED also is ON when the resistor is resent. The voltage sense feature is handled by IO-pin P0.23, which is connected to VCC of the USB interface.

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Figure 7 - LPC2148 Education Board Schematic, page 1: USB

2.1.5 Page 1: JTAG

The JTAG interface is a standard 20-pin (2x10) connector with shoulders – ‘standard’, at least in the ARM world. The JTAG interface shares 6 general IO-pins (GPIOs) and is enabled by shorting jumper J9, i.e., pulling P1.26 low during reset. When the JTAG interface is enabled, the 6 IO-pins cannot be used for other purposes than the JTAG interface. Figure 8 below illustrates the JTAG part of the schematics.

Figure 8 - LPC2148 Education Board Schematic, page 1: JTAG

To use the JTAG interface of the LPC2148 Education Board a special JTAG interface pod must be used. This pod must be integrated with a debugger in order to do anything useful with it. There exist many different manufacturers of JTAG interface pods.

2.1.6 Page 1: Expansion Connector

The LPC2148 Education Board is not just a monolithic design. Via the expansion connector, it’s possible to expand the design. All LPC2148 pins are available on the expansion connector, which is a standard 2x32 pin list with 100 mil pin spacing. Figure 9 below illustrates the expansion connector part of the design.

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Embedded Artists AB LPC2148 User Guide

Specifications and Main Features

Frequently Asked Questions

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