What can we see from this plot?
•
Even lower power consumption with the LED OFF
Result: Using the Watchdog Timer as the wake-up source allows us to use the lowest power Sleep mode
in this example.
Now let's take a brief and closer look at the details of our plots. Enabling cursors allows us to take more accurate
measurements from the plot.
To do:
•
Open the Control Panel in the upper right corner of the Power Analysis module
•
Expand the Cursors section
•
Click the Enabled box to turn the cursors on
In the plot above we use two cursors to first check the delta - confirming that the Watchdog Timer interrupts
approximately every second, as expected.
Zooming further in we can see that the width of the 'on' pulse (shown as Cursor Delta) is a little over 33 ms. This
equates to a duty-cycle of 3.3% - a touch higher than intended (1%). The main clock is 16 MHz at 5V, and we are
using DIV64 CLKPR, and DIV32 on TIMER2, giving it a 128 μs tick. With overflow every 256 cycles the LED on
period is thus 32.7 ms, close to our measurement. So to achieve a 1% duty-cycle TIMER2 preload value can be
increased from 0x00 to 0xB2.
©
2020 Microchip Technology Inc.
Remember: If the current measurements are still running, make sure to disable Auto-scroll
before enabling the cursors, or else the graph view will rapidly scroll away from the cursors.
User Guide
Power Debugger
Detailed Use Cases
DS40002201A-page 24
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