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Elektor

Blockbusters

Top-15 articles from Elektor

Elektor blockbusters

Artikeltitel • 1

Contents

Elektor RFID Reader ........................................................................................................ 3

Stand Alone OBD-2 Analyser ......................................................................................... 11

ElekTrack ....................................................................................................................... 18

Making Waves at C ........................................................................................................ 24

Digital Inspector ............................................................................................................ 27

Proﬁler .......................................................................................................................... 31

ECIO PLC ........................................................................................................................ 36

Universal JTAG Adaptor ................................................................................................. 41

GBECG ............................................................................................................................ 47

Tilt Gamepad ....................................................................................................... 57

Micro Webserver .................................................................................................. 60

Software Deﬁned Radio ................................................................................................ 68

Wireless USB in miniature ............................................................................................. 74

A 16-bit Tom Thumb ...................................................................................................... 82

USB Flash Board ............................................................................................................ 89

Elektor blockbusters

Contents • 2

HANDS - ON MICROCONTROLLERS

ELEKTOR RFID Reader

Gerhard H. Schalk

RFID cards are becoming

increasingly popular in

many fields where

previously barcodes and chip

cards were used. They open

up many new possibilities, such

as applications in travel cards or

even banknotes. As befits a

premier electronics magazine,

Elektor Electronics is offering its

readers with this issue not only a

free RFID card but also a professional

RFID reader for your own applications.

The design described here can both read

from and write to all types of RFID card

that are compatible with the MIFARE and

ISO 14443-A international standards.

In developing the Elektor Electronics

RFID reader we have aimed to make

the device as universal as possible. So,

for example, the reader can be used in

conjunction with a PC over a USB con-

nection, or in stand-alone mode using

its liquid crystal display. It is very sim-

ple to use the free PC-based program

‘MIFARE Magic’ to read and write all

kinds of MIFARE cards without

installing special software in the

reader.

Elektor blockbusters

Elektor RFID Reader • 3

For MIFARE ® and ISO 14443-A cards

elektor electronics - 9/2006

Specifications

• Available as ready populated and tested SMD circuit

board

• Can be modified for user applications

• Programming tools available

Elektor Electronics RFID reader:

• Near-field reader for 13.56 MHz RFID cards

• Compatible with MIFARE and ISO 14443-A cards

• Allows both reading and writing

• USB interface for connection to PC

• Ready for immediate use without programming

• Free PC-based software available

• Stand-alone (including portable) operation using LCD

module

• Dedicated MF RC522 reader IC

• Dedicated microcontroller on reader board

• SPI and I 2 C interfaces

• Spare 8-bit microcontroller port

• Buffered switching output

MF RC522 reader IC:

• Highly-integrated single-chip reader for ISO 14443-A and

MIFARE cards

• Supports contactless data transmission at 106 kbit/s,

212 kbit/s and 424 kbit/s

• 50 mm approx. read/write range (depending on antenna)

• Integrated MIFARE Classic cryptography

• Programmable over UART, I 2 C or SPI

• 64 byte transmit and receive FIFO buffer

• Programmable reset and power-down modes

• Programmable timer

• Internal oscillator allows direct connection of 27.12 MHz

crystal

MIFARE Magic directly supports a

range of contactless 13.56 MHz

MIFARE cards, including the Philips

MIFARE UltraLight, MIFARE 1K and

MIFARE 4K. The MIFARE Magic win-

dow ( Figure 1 ) also offers the facility

to send individual commands to the

card with a click of the mouse. This

allows you to determine the character-

istics of different cards very easily.

Examples of compatible cards include

the MIFARE UltraLight RFID card sup-

plied with this issue, and described in

more detail in a separate article, and

smart cards used on many public

transport systems all over the world —

for example, the London Underground

Oyster card

In stand-alone operation, for example

in an access control application, the

reader can be used directly with the

firmware we have developed. On

switch-on the reader immediately

looks for cards within the range of the

antenna (a few centimetres) and reads

any cards it finds in that area. The LCD

(if connected) then shows the card

type along with its serial number, and

the switching output of the reader is

activated.

The reader is constructed around the

newest Philips reader IC type

MF RC522 and a type LPC936 micro-

controller. Since the reader IC is only

available in an HVQFN32 package, we

have decided to solve the problems of

mounting and soldering by making

available ready populated and tested

reader boards fitted with pre-pro-

grammed microcontrollers.

The Elektor Electronics RFID reader is

naturally ideal for experimenting with

the free MIFARE UltraLight card. The

system includes a powerful microcon-

troller and I 2 C, SPI, UART and USB

interfaces, and free development tools

are available. This makes it suitable for

developing dedicated applications

such as door and gate openers, mem-

bership card systems, storing pass-

words and configuration data, pay-

ment systems, security for domestic

appliances such as televisions, video

recorders and PCs, monitoring battery

Figure 1. The MIFARE Magic program developed for the Elektor Electronics RFID reader allows MIFARE and

ISO 14443-A RFID cards to be read, written and programmed.

Elektor blockbusters

9/2006 - elektor electronics

Elektor RFID Reader • 4

HANDS - ON MICROCONTROLLERS

RFID Reader

LCD

I /O

I 2 C

vides the 3.3 V supply for the LPC

microcontroller (IC3) and the

MF RC522 (IC4). Red LED D6 shows

when the 3.3 V supply is present. If 5 V

power is not provided via the USB con-

nector Schottky diode D4 allows an

external power supply to take over

automatically. Either four AA-size cells

(the enclosure suggested in the parts

list will accept these) or a 5 V mains

supply capable of delivering at least

300 mA can be used.

Figure 4 shows an overview of the

internal functions of the MF RC522

reader IC in the form of a (greatly sim-

plified) block diagram. The output driv-

ers of the device allow direct connec-

tion of transmit and receive antennas

without external active amplification

circuitry. A few passive components

provide the essential matching to the

antenna characteristics. The analogue

interface handles demodulation and

decoding of the reply data sent by the

card. The digital block is responsible

for constructing the ISO 14443A or

MIFARE protocol frames and accompa-

nying error detection (parity and CRC).

The FIFO buffer allows 64-byte blocks

to be sent and received in ISO 14443

mode (‘T=CL’ protocol). In MIFARE

mode the largest data blocks

exchanged are at most 16 bytes long,

and so there is no need for the micro-

controller to split up the command

packets. The registers of the MF RC522

can be programmed over the SPI, asyn-

chronous serial or I 2 C interfaces. Since

the LPC936 microcontroller only has

one asynchronous serial interface, and

this is required for communications

with the PC, the I 2 C interface is used

to talk to the MF RC522.

If desired an LCD module can be con-

nected to port P0 of the LPC936 via

connector K2. P0.0 is buffered by a

transistor and provides a switched out-

put, and the SPI and I 2 C interfaces of

the microcontroller afford plenty of

opportunities to expand the reader by

adding extra hardware. For example, a

real-time clock could easily be added

to allow for time monitoring, and the

switched output could control a door

opener; see also the pages about the

RFID reader on the Elektor Electronics

website.

MF RC522

I 2 C

M C / Philips

LPC 935

RS232

Voltage

Regulator

FT232R

USB / UART

USB

Optional Power Supply

060132 - 13

Figure 2. Block diagram of the Elektor Electronics RFID reader.

packs and much more besides. The

combination of secure identity, data

storage and contactless interface

opens up many opportunities for novel

applications.

memory are sufficient for an enormous

range of possible applications. Pro-

grams for the microcontroller can be

simply written using any 8051 com-

piler. Communications with the PC are

handled by an FT232R USB/RS232

interface chip from our friends at

Future Technology Devices (FTDI).

The full circuit diagram is shown in

Figure 3 . When connected to a PC,

power is taken from the USB via mini-

connector K1. The FT232R USB inter-

face chip is configured to report the

reader as a high-power device when

the bus is initialised (during ‘enumer-

ation’). As a bus-powered device the

reader can then draw a current of up to

500 mA. When enumeration is com-

plete the /PWRNEN signal on pin 11 of

IC1 changes state, making P-channel

MOSFET T2 conduct. The 5 V supply is

then passed through to voltage regula-

tor IC5. The output of the LM2937 pro-

Reader hardware

Figure 2 shows the block diagram of

the reader. The basic reader functions,

including the creation of the HF mag-

netic field, modulation and demodula-

tion, and the generation of the

ISO 14443 data stream, are carried out

in the MF RC522. It is simplest to think

of the MF RC522 as a contactless

UART driven directly by the microcon-

troller. In the Elektor Electronics reader

we have used an 8051-compatible

LPC936 microcontroller from Philips.

The CPU takes only two cycles per

instruction and is clocked at 16 MHz.

This speed and the 16 kbyte Flash

Analog

Interface

Contactless

UART

FIFO

Serial UART

SPI

I 2 C

Host

MFRC5222

060132 - 14

Get started

The double-sided printed circuit board

for the Elektor Electronics RFID reader

is shown in Figure 5 . It is only possi-

ble to reflow solder the reader IC, and

so we are making the board available

Figure 4. Block diagram of the Philips MF RC522 reader IC.

Elektor blockbusters

Elektor RFID Reader • 5

elektor electronics - 9/2006

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