© Copyright ARM Limited 2016. All rights reserved.
WH000
ARM-EPM-1017464.0
Confidential
Page 17
5
CURRENT MEASUREMENT
The current drain for the BT4 Radio IP can be measured independently from current required by the rest of the
BT4 Demonstration SoC. Current measurement can be done while the BT4 Radio IP is running in either 1 volt or 3
volt mode.
5.1
Considerations
PLEASE NOTE:
Any current meter used to measure current drain must
not
be set for
“
auto-ranging
”
, particularly
if standby current is to be measured. Many meters are poorly regulated and/or have large time constants that can
cause overvoltage situations while switching ranges. This can cause permanent damage to the BT4 SoC and/or
Radio IP block.
To access the appropriate current measurement points, please measure current when operating the Eval board in
5 volt Line powered mode vs. being battery powered. To ensure you are operating in this mode, check that the
Power Mode switch located along the middle right edge of the board is in the
“
Line
”
position as described in
section 3.2.1.
5.2
1 Volt Mode
– Current Measurement
With the Evaluation board powered down (5 volt power removed from the board), place the 1V / 3V switch
(located along the top right edge of the board) in the 1 volt mode by sliding the switch upwards. (See Section
3.2.33.2).
With power still removed from the board, remove the jumper from J30 (located just above the ARM mbed logo).
Attach your desired current measuring equipment across the two lower pins of the connector as shown below. The
center pin, Pin 2 on the connector, is the downstream voltage supply rail to the BT4 SoC. Pin 3 on the bottom of
the J30 header of the board is the 1 volt supply coming from the LDO regulator. If a GND reference is needed,
please use Pin 1 (the upper most pin on J30) or ground test point (TP13) just to the left of J30 as shown in the
diagram below.
Figure 5.2
– 1 Volt Test Point