User's Manual

14/07/16 Page 13 of 18

ABR200 Integration Manual

5.2 USB interface

The USB interface of the ABR200 is provided by the processor on the module. The interface uses

USB-CDC (USB Communication Device Class). This is different to the previous reader module

ABR105, which used an FTDI USB chip.

The USB data lines (USB-DP and USB-DM) are using a level of 3.3V as per USB specification.

The diagram above shows how to connect USB on the ABR200.

For USB the configured baud rate does not matter since the devices are negotiating the

communication speed on their own in case of USB.

Agrident can already provide a USB driver installer for Windows desktop computers. Currently

we are working on a solution for a driver for Windows CE and Windows Mobile. A driver for

Android devices should be available here: https://code.google.com/p/usb-serial-for-android/.

6 The GPIOs

There are five GPIOs available on the ABR200. At the moment they are used for the following

purposes:

GPIO

Input /

Output

Function

Description

Output

Read

indicates a successful tag read

Output

RF-On

indicates that the RF-field is activated

Output

Power

indicates that the module power is switched on

RFU

reserved for future use

Output

PWM_Out

PWM output for synchronizing external switch-mode

regulators; frequency depends on BAT-IN voltage

All GPIOs have 1KΩ series resistors on the ABR200 for current limiting and thus protecting the

modules processor.

If you want to indicate particular events with LEDs directly from the ABR200 GPIOs, you have to

use additional transistors. The GPIOs themselves cannot drive LEDs.

If you do not use particular GPIOs, please leave those pins open!