Testing Board Features
2016 Microchip Technology Inc. DS50002480A-page 25
3.3.2.2 WARNINGS AND CONSIDERATIONS
• When measuring the current/power consumption, it is recommended to connect
the loads (devices) that do not draw a current above ~2.5A.
• A shunt resistor of 0.025Ω is used, which sets the PAC1710 chip’s full-scale cur-
rent value to 3.2A. However, current limitations are also imposed by the MCP2221
board’s design.
• In case of continuous measurement, samples are taken once every 100 milliseconds,
so higher frequency variations may not be noticed by the application.
• The software provides the option not to display specific variations (such as popu-
lating the voltage graph, for example) to reduce the amount of tasks that the PC
must perform. This is especially useful when the PC is running low on system
resources (like processor usage or memory filling).
• Even when switching to a different tab (such as measuring resistors), if the
monitoring is enabled, then it will not be automatically halted unless the board is
physically disconnected from the PC. Therefore, it is recommended to stop
performing the measurements when they are no longer required.
3.3.2.3 NOTIFICATIONS FUNCTIONALITY
The MCP2221 board also provides three access points (TP3, TP4 and TP5), described
in Section 2.3 “Jumpers and Connectors Description”.
The PAC1710 chip can be configured to signal notifications via the ALERT
pin that’s
connected to the TP3 test point of the MCP2221 I
2
C Demonstration Board.
For custom measurements, it’s highly recommended to read the data sheet for the
PAC1710 chip, as well as view the schematic and layouts of the board, available in
Appendix A. “Schematics and Layouts” of this document.
3.3.3 Measure Temperature Tab
The temperature sensor is built into the MCP9808 chip. The sensor’s accuracy
depends on the temperature value intervals, as seen in the following table:
In the case of continuous monitoring, samples are taken once every 100 milliseconds,
so higher frequency variations may not be noticed by the software.
The software provides the option not to display specific variations (for example, popu-
lating the temperature graph) to reduce the amount of tasks that the PC must perform.
This is especially useful when the PC is running low on system resources (such as
processor usage or memory filling).
Even when switching to a different application tab, if the monitoring is enabled, then it
will not be automatically halted unless the board is physically disconnected from the
PC. Therefore, it is recommended to stop performing the measurements when they are
no longer required.
Temperature Value Intervals Accuracy
-40°C to +125°C ±0.25° (typical)
-20°C to +100°C ±0.5°C (maximum)
-40°C to +125°C ±1°C (maximum)
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