WICED Evaluation Board
WICED™ Evaluation Board User Guide
Doc. No.: 002-19353 Rev. *A
7
2.4 Power Supply
Power is provided to the EVB via the USB interface or ex5V connector independently or concurrently. Use of the
ex5V power supply is recommended if a device connected to the expansion header consumes more than 100mA
of current.
2.5 Power Consumption Measurement
A dedicated current measurement circuit is included on the EVB to enable system-level power profiling of applications
running on the WICED module. The circuit is based on a Maxim MAX4376 current-sense amplifier that measures the
differential voltage across a 0.2 Ohm resistor in series with the module power supply.
The current consumption profile of the application running on the WICED module is measured by connecting an
oscilloscope across the header pins marked CURRENT and GND. The output voltage of the circuit is scaled to produce
1V for every 100mA (or 10V for every 1A) of current consumed. The power consumption of the module is calculated by
multiplying current consumption by the VDD_3V3 voltage.
A current consumption profile of the WICED module obtained during boot and Wi-Fi association of a WICED SDK
example application is shown in
. The plot is provided as an example profile only. Actual power consumption
will vary depending on the WICED module, application and SDK version, hence the vertical scale has been removed.
Note
: The current measurement circuit has limited accuracy below 5 mA and is therefore not suitable for low-range sleep
current measurements.
Figure 2-2. Example current consumption profile
2.6 Program & Debug Interfaces
The WICED EVB provides two independent interfaces for programming the microcontroller on the WICED module, a
USB-JTAG interface and a J-Link JTAG interface.
The WICED SDK uses the USB interface for programming and debugging by default. To use the USB interface, connect
the WICED EVB directly to a PC containing the WICED SDK. A driver for the board was installed during the SDK
installation process.
To use the J-Link direct JTAG interface, ensure the board is powered, then connect the J-Link JTAG programmer to the
JTAG header marked JLINK. To override the default USB programming interface, the
JTAG=jlink
option must be
provided to the WICED SDK toolchain.
Low-cost JTAG programmers that connect to the WICED EVB J-Link header are available from
. The WICED SDK
provides instructions to use Olimex JTAG programmers at the following location :
<WICED-SDK>/Tools/OpenOCD/Olimex_README.txt
During programming and debug, the JTAG LED flashes intermittently on and off.
