No Target Voltage and PS LED is Lit 1
This occurs if the target voltage is set to 0.0V. To fix this, set the target voltage to a value within the specified voltage
range for the target device.
No Target Voltage and PS LED is Lit 2
This can be the issue if power jumper J100 and/or J101 is cut, and the target voltage regulator is set to a value within
the specified voltage range for the target device. To fix this, solder a wire/bridge between the pads for J100/J101, or
add a jumper on J101 if a pin header is mounted.
VBUS Output Voltage is Low or Not Present
This is most lightly caused by a high-current drain on VBUS, and the protection fuse (PTC) will reduce the current or
cut off completely. Reduce the current consumption on the VBUS pin to fix this issue.
4.4
Low-Power Measurement
Power to the AVR128DB48 is connected from the on-board power supply and
VTG
pin through a 100 mil pin header
marked with “POWER” in silkscreen (J101). To measure the power consumption of the AVR128DB48 and other
peripherals connected to the board, cut the
Target Power strap
and connect an ammeter over the strap.
To measure the lowest possible power consumption follow these steps:
1.
Cut the POWER strap with a sharp tool.
2.
Solder a 1x2 100 mil pin header in the footprint.
3.
Connect an ammeter to the pin header.
4.
Write firmware that:
4.1.
Tri-states any I/O connected to the on-board debugger.
4.2.
Sets the microcontroller in its lowest power Sleep state.
5.
Program the firmware into the AVR128DB48.
Figure 4-7. Target Power Strap
Target Power strap (top side)
AVR128DB48 Curiosity Nano
Curiosity Nano
©
2020 Microchip Technology Inc.
User Guide
DS50003037A-page 19
