AVR16EB32 datasheet(27/46 Pages) MICROCHIP

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AVR16EB32 Curiosity Nano

Hardware Implementation

User Guide

DS50003605B - 27

No, or Very Low Target Voltage and PS LED is Blinking Rapidly

A full or partial short circuit can cause this and is a particular case of the issue above. Remove it, and

the on-board debugger will re-enable the on-board target voltage regulator.

No Target Voltage and PS LED is Lit 1

This situation occurs if the target voltage is set to 0.0V. Set the target voltage to a value within the

specified voltage range for the target device to fix this.

No Target Voltage and PS LED is Lit 2

This situation can be the issue when cutting power jumper J200 and/or J201 and setting the target

voltage regulator to a value within the specified voltage range for the target device. To fix this, solder

a wire/bridge between the pads for J200/J201 or add a jumper on J201 if a pin-header is mounted.

VBUS Output Voltage is Low or Not Present

If the VBUS output voltage is low or missing, the reason is probably a high-current drain on VBUS,

and the current limit set by U202 (MIC2008) is tripped and has cut off VBUS completely. Reduce the

current consumption on the VBUS pin to fix this issue.

4.4.5

Low-Power Measurement

Power to the AVR16EB32 comes from the on-board power supply and

VTG pin through a 100 mil

pin-header marked with “POWER” in silkscreen (J201). To measure the power consumption of the

AVR16EB32 and other peripherals connected to the board, cut the

Target Power strap (J201) on the

bottom side and connect an ammeter across it.

Tip: A 100-mil pin-header can be soldered into the

Target Power strap (J201)

footprint for a simple connection of an ammeter. Place a jumper cap on the

pin-header once the ammeter is no longer needed.

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:

a. Tri-states any I/O connected to the on-board debugger.

b. Sets the microcontroller in its lowest Power sleep mode.

5. Program the firmware into the AVR16EB32.

Info: The on-board level shifters will draw a small amount of current even when

unused. Each level shifter has a maximum of 2 μA leakage current. Therefore, the

worst-case maximum current draw for the five on-board level shifters is 10 μA.

Prevent leakage current through an I/O pin connected to a level shifter by keeping

the I/O pin tri-stated. All I/Os connected to the on-board debugger are listed in

On-Board Debugger Connections. The on-board level shifters can be completely

disconnected, preventing leakage, as described in Disconnecting the On-Board

Debugger.

4.4.6

VBUS Output Pin

AVR16EB32 Curiosity Nano has a VBUS output pin that can be used to power external components

that need a 5V supply. The VBUS output pin is protected by the same start-up delay with a slew

rate and current limiter as the rest of the power supply. A side effect is a voltage drop on the VBUS

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