B i o m e t r i c - E X P E V B
8
Rev. 0.4
4. USB Debug Mode
The Biometric-EXP demo firmware includes a debug mode that enables Heart Rate Monitor and SpO2 raw
samples from the sensor to be streamed to a host PC via the Gecko STK’s USB interface. Only HRM and SpO2
data is available via the USB debug interface. UV, Relative Humidity, and Temperature data is not available.
Enabling and connecting to USB debug mode is illustrated in Figure 7 and is described in the following sections.
Figure 7. Enabling and Connecting to USB Debug Mode
4.1. Enabling USB Debug Mode
In order to maintain power efficiency of the demo, the USB debug mode is disabled by default. The LCD will show
“USB OFF” during startup. To enable USB debug mode, the user must hold down button PB0 then press and
release the Reset button. Both buttons are on the Gecko STK as shown in Figure 7. The user should hold down
PB0 until the LCD shows “USB ON.” At this point, USB is enabled and the demo will run normally. To later disable
USB debug mode the user can press the Reset button without holding PB0.
4.2. Connecting to USB Debug Mode on a PC
Prior to using USB debug mode, the user must first install the Biometric-EXP Windows Evaluation Software. This
will install the Windows applications and drivers necessary to use USB debug mode. The Gecko STK has two USB
type connectors: a USB Mini type connector labeled J-Link on the short side of the EVB and a USB Micro type
connector on the long side of the EVB. The USB Micro connector is used for the USB debug interface, as shown in
Figure 7. In addition to using the correct physical interface, the Power Source Select switch must be set to USB
(center position) for proper operation.
USB debug mode utilizes a Virtual COM Port (VCP) interface to communicate between the Biometric-EXP demo
and the PC. With the Windows software installed, USB debug mode enabled on the Wonder Gecko and a USB
cable connecting the Wonder Gecko STK and the PC, the device will appear in Windows Device Manager as a
COM port as shown in Figure 8.
The J-Link USB mini connector is
not
used for
the Biometric-EXP demo debug interface. It is
only used to load firmware and for firmware
development
The USB micro connector
is
used as the
Biometric-EXP demo debug interface.
The Power Source Select Switch should
be set to USB to enable the debug
interface
To enable USB Debug Mode, hold down
PB0 and press Reset. Continue holding
PB0 until the display shows USB ON
