Using the Energy Probe
ARM DUI 0482K
Copyright © 2010-2012 ARM. All rights reserved.
12-5
ID120712
Non-Confidential
12.3
Energy Probe setup
When first plugging in the Energy Probe on Windows, the LED flashes RED at approximately
one second intervals. This indicates the USB enumeration has failed and that you must install
the driver. To install, use the standard Windows driver installation wizard and, if required, select
the
ARM_EnergyProbe.inf
configuration file. This file is located in
install_directory
/sw/energy
probe/
. There is no driver DLL, because Energy Probe uses the built-in USB CDC virtual serial
port functionality on both Windows and Linux.
To setup on Linux Ubuntu, enter the following command:
sudo apt-get install libudev-dev
On Linux Ubuntu, you must either change the permissions of the
tty
device or add yourself to
the
dialout
group for Energy Probe to successfully use the device. To change the permissions
of the
tty
device, use the following command:
chmod 777
tty_location
Note
/dev/ttyACM0
is the usual location of the
tty
device.
As an alternative, you can add yourself to the same group as the tty device. To do so, enter the
following command:
usermod -a -G
Group_Name
User_Name
Note
dialout
is the usual name of the group for the
tty
device.
When you have installed the driver and it is operating correctly, the LED remains green.
Attaching a probe backwards to Energy Probe or the target causes the LED to turn red.
Backwards connections do not damage your target or Energy Probe but this kind of connection
does not provide useful data. Disconnect all Energy Probe probes and wait until the LED
changes to green, then reattach one by one and make sure to reverse the polarity on any probe
that results in the LED changing to red. When you have attached the Energy Probe correctly, the
LED remains green.
Note
In case of low consumption, it is possible that the LED remains red even if the connection is
right. This might happen if the target device is idle.
Caution
The Energy Probe requires a common ground between the probe and the target. Take special
care when first attaching the ground pin and the probes. The following symptoms are an
indication that you have attached to the wrong testpoint:
•
the LEDs on your target suddenly turn off
•
the Energy Probe LED turns off
•
you hear a buzzing sound from the board or the power supply.
Quickly remove the probe from the target and check you have not damaged your target.