User manual

Atmel AT02657: XMEGA-E5 Xplained Software User Guide [APPLICATION NOTE]
42085A−AVR−04/2013
5
1.3.1 USB Communication Device Class
The CDC interface uses the native driver from UNIX
®
O.S., but requires a specific one on Windows
®
O.S. available in
the example. The atmel_devices_cdc.inf file can be selected to install the new USB CDC interface.
After having installed the CDC driver, the Virtual COM port can be opened through a terminal.
Note: The Virtual COM port is not connected to a true RS232 COM port, however, the ATxmega32E5 device
communicates with the AT32UC3B1 board controller on the USART at 38400 bauds, 1 stop bit, and no
parity. So the terminal must be configured accordingly.
1.4 Running the demo application
• Startup
The Atmel XMEGA-E5 Xplained kit is powered through the USB connector. The display first shows explanation of how
to use the demonstration, SW1 pressed will skip this explanation.
• Light sensor acquisition running
The application starts a sensor acquisition task scheduled by the real-time counter (RTC). The light sensor values are
displayed on the OLED.
The Quadrature Encoder (SW2) is used to control the sampling rate. There are 20 positions to select a sampling rate
from 0.5s to 10.5s per 0.5s step.
CPU load
S am p lin g
Light
0.5s
CPU activity varies according to actions on the Quadrature Encoder. When no change in the sampling rate, display
shows a low CPU load while this will increase when changing this rate.