User manual

Atmel AVR1939: XMEGA-C3 Xplained Getting Started Guide [APPLICATION NOTE]

42054A−AVR−02/2013

2. Quick-start

To be able to run the preprogrammed code, you need to connect the Atmel AVR XMEGA-C3 Xplained evaluation kit

with a USB cable (standard A to mini-B or mini AB) to a PC or USB hub.

Once the kit is powered, the display first shows explanation of how to use the demonstration; SW1 pressed will skip this

explanation.

The application starts then a sensor acquisition task scheduled by the real-time counter (RTC). The temperature and

light sensors values are displayed on the OLED. Pressing QTB0 increases sampling rate per 0.5s. Pressing QTB1 de-

creases sampling rate per 0.5s.

Figure 2-1. Default display during sensors acquisition.

When a microSD card is inserted, microSD icon is displayed. During microSD card installation, a rectangle shows the

read/write access and the CPU load is increased consequently.

Figure 2-2. Display when microSD card is active.

uSD

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Pressing SW0 activates USB, the USB icon is displayed.

Figure 2-3. Display when USB is activated.

Figure 2-4. Display when the USB Host opens the Virtual Port.

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CPU activity varies according to demo modes. When USB is activated, display will show a CPU load light increase while

USB Host accesses to microSD with multiple read/write operations will increase consequently this CPU load.

The demo application allows also the XMEGA-C3 Xplained board to communicate with a USB device composite includ-

ing:

• a USB Mass Storage Class (MSC)

• a USB Communication Device Class (CDC)

The MSC interface uses the native driver from USB host O.S. and does not require a specific setup. Thus, the microSD

card is mounted as an external disk in O.S.