Datasheet

NXP Semiconductors

AN11116

Using the RS232 serial evaluation boards on a USB port

AN11116

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Application note

COMPANY PUBLIC

Rev. 1.1 — 1 August 2012

215111

3 of 8

1. Introduction

1.1 Introduction

NXP provides various development boards for systems supporting ISO/IEC14443 based

contactless reader technology. Products are for example MFRC663,

MFRC522, MFRC523,

MFRC52x, MFRD522, MFRD523, MFRD52x,

PN512 and PN532.

The development boards make use of an serial RS232 interface which is connected to a

PC to execute scripts or other PC based software to control the functionality of the

contactless reader IC.

More and more it is found that modern PC’s are not equipped by default with the RS232

interface.

A standard interface available on most PCs is the USB interface. Converters that are

converting the signals of a USB interface to RS232 signals are available in the market.

In practice we have found that not all USB /RS232 converters are working without

problems. Reason for this problems could be that the designers of this interfaces need to

find a compromise to fit most applications, so that it does not fit very well to the use case

of transferring contactless data.

1.2 Scope

This document describes which interface converter ad been found to work well with the

NXP development boards. The settings to operate the interface with the NXP

development boards will be given.

1.3 Hardware

The interface IC’s which had been found to work well are the ones from the company

FTDI (http://www.ftdichip.com).

To allow USB converter chip to communicate with a PC, suitable USB drivers are

required to be installed on the PC. These can be downloaded from the FTDI website.

To verify that the DB9-USB-RS232 is communicating with the PC, an enumeration check

can be carried out using a utility program called “USB View”. This is also available from

the FTDI website.

Alternative, the device manager can be used to check if a new USB device is available

after installation.