UM11673
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© NXP B.V. 2021. All rights reserved.
User manual
Rev. 1.0 — 13 September 2021
10 of 15
NXP Semiconductors
UM11673
MCU-Link Pro
not necessary to disconnect / reconnect the MCU-Link Pro. It is recommend to power the
MCU-Link Pro first when not using the MCU-Link Pro to power the target as the MCU-Link
could be back-powered through the current measurement circuit.
The power measurement feature is intended for low power measurements, with a target
MCU running at up to 3.6V. The design uses the LPC55S69 16-bit ADC, with power data
sampled at up to 100kS/s. At high sample rates MCUXpresso IDE may not be able to
capture all data, so the sample rate may need to be adjusted using the configuration
options in the Energy Measurement configuration settings in that tool.
4.4.1 Measurement range configuration
As mentioned above, MCU-Link Pro has two maximum current range measurement
configurations, with the lower range providing better resolution at very low currents. If the
target current exceeds the maximum current for the selected range then the measurement
will clip and hence be inaccurate, but the target operation may continue as normal
(provided the current is not high enough to cause a significant drop across the high
current sense resistor and hence cause a brown out and/or trigger glitch security
protection on some devices). Note that the MCU-Link Pro on-board regulator for the target
is limited to a maximum of 350mA output.
Range configuration settings with corresponding accuracy and resolution are shown
below. Note that all settings for J16/J17/J18 must be consistent for correct operation.
Accuracy may vary with temperature and is provided for reference purposes only.
4.5 SPI and I2C bridging (USB to Target SPI and/or I2C bridge, USBSIO)
MCU-Link Pro includes a capability to bridge SPI and/or I2C ports to a host computer via
USB, called USBSIO. This port bridging function can be used for emulating a system host,
peripherals (in the case of I2C) and/or for device programming via the ISP feature. NXP’s
MCUXpresso SEC tool has an option to program a target system via this bridge (see SEC
tool documentation for details). USBSIO activity is indicated by the USBSIO status LED,
which will illuminate/flicker when traffic is present on this interface. This feature is
supported by a free host library from NXP called LIBUSBSIO; for more details on this
library please visit
The SPI interface connections are routed via level shifters/buffers with the target side IO
voltage determined by the voltage connected to the VDD_IO_REF signal at pin 14 of J19.
The I2C interface connections are routed to an open drain buffer on the MCU-Link Pro.
USBSIO may be disabled by inserting jumper J15 before powering the MCU-Link Pro; this
will instruct the firmware not to enumerate the USB end point for USBSIO (which is called
“MCU-Link LPCSIO” for backward compatibility reasons). Note that installing/removing
this jumper after powering the board will have no effect on the feature in terms of how the
Table 3.
Energy measurement range configuration (as at firmware revision 2.243)
Maximum measureable
current
J16
setting
J17
setting
J18
setting
Measurement
ranges
Resolution Accuracy
(typical)
50mA
2-3
2-3
2-3
200nA to 400uA
>400uA to 50mA
200nA
5uA
1%
1%
350mA
1-2
1-2
1-2
10uA to 1.5mA
>1.5mA to 350mA
1uA
20uA
1%
5%