Programming And Debugging; Analog Hardware - Microchip Technology Power Debugger Manual

processed. The microcontroller includes an on-chip USB 2.0 high-speed module, allowing high data throughput to
and from the tool.
5.2

Programming and Debugging

The debugger section of the Power Debugger closely resembles the Atmel-ICE hardware. At the heart of the
debugger is the Microchip AVR UC3 microcontroller, which implements a USB HID interface for its programming and
debugging API.
Communication between the Power Debugger and the programming and debugging interface on the target device is
done through a bank of level converters that shift signals between the target's operating voltage and the internal
voltage level on the Power Debugger. Also in the signal path are PTC fuses, Zener over-voltage protection diodes to
ground, series termination resistors, inductive filters, and ESD protection diodes. All signal channels can be operated
in the range 1.62 to 5.5V, although the Power Debugger hardware itself can not drive out a higher voltage than 5.0V.
Maximum operating frequency varies according to the target interface in use.
The Power Debugger includes three electrically connected output ports for convenience. The two 50-mil horizontal
headers are for use with AVR 10-pin pinout and the ARM Cortex debug headers, respectively. These ports are
identical to those found on the Atmel-ICE. In addition the Power Debugger includes an unpopulated 100-mil header in
the AVR pinout for custom connections.
Important: Soldering onto this header is done at the user's risk, and ESD precautions must be taken.
5.3

Analog Hardware

The Power Debugger analog front-end contains two channels, referred to as the 'A' channel and the 'B' channel.
Although they operate on similar mechanisms, the two channels are not symmetrical and should be used for different
purposes.
Both channels are fed into independent ADC channels on the AVR XMEGA128A1U microcontroller. This ADC
module allows for the 'A' channel to operate totally independently at maximum sampling rate while the 'B' channel
ADC is shared with both channels' voltage measurement, which are sampled less frequently.
The 'A' channel is the recommended channel for accurately measuring low currents. It features two shunt stages,
which through bypass switches, provide a circuit capable of measuring from 100 mA on the top-end down to under 1
μA. Range switching is done automatically, and it is possible to lock sampling into the high-range only should this be
needed.
1. 'A' channel high range: 100 mA - 500 μA, ~3 μA resolution.
2. 'A' channel low-range: 1 mA - 1 μA, ~30 nA resolution.
The sampling rate of the 'A' channel is 62.5 kHz and data is sent in 16-bit frames to the host computer. A calibrated
'A' channel has accuracy no worse than 3% down to around 1 μA.
The 'B' channel is the recommended channel for measuring higher currents with lower resolution than the 'A'
channel. It is based on a single shunt resistor allowing measurement of current up to 1A and down to 1 mA.
1. 'B' channel single range: 1A, ~500 μA resolution.
Data is sampled at 62.5 kHz and transferred to the computer in 12-bit frames.
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2020 Microchip Technology Inc.
User Guide
Power Debugger
Hardware Description
DS40002201A-page 78