Graphical Display of Power Monitoring Data
Display of power monitoring information in tabular format is good, but a visual representation of the values over time is far more engaging and readable. To this end, the power monitoring facility offers the ability to display the monitored information graphically.
All information available in the Power Monitor panel can be enabled for display in a number of charts within Altium Designer's Sim Data Editor. Use the Graphing Options region of the Power Monitor Options dialog to enable the charts required.
Figure 1. Enable graphing options in the Power Monitor Options dialog.
Graphing itself is only possible provided polling is enabled. Graphing can be started/stopped in a number of ways:
- From the NanoBoard's Instrument panel – either use the Start Graphing button (which changes to Stop Graphing button) or the Graphing LED, to toggle graphing ON/OFF.
- From the Power Monitor panel – use the Enable Graphing option to toggle graphing ON/OFF.
Figure 2. Start graphing the data for the monitored
power lines.
Once enabled, the monitored data and resulting waveforms will be written to a Simulation Data File (*.sdf) and displayed within a multi-tabbed waveform analysis window – presented in the Sim Data Editor.
Figure 3 illustrates graphing of results for a Desktop NanoBoard that has three peripheral boards and a daughter board attached.
Figure 3. Charts, wave plots and waveforms, all displayed in the integrated Sim Data Editor.
As can be seen, each chart is available on a separate tab. The active chart in this case is the Summary chart, which contains two plots. The first plot – entitled Power Summary – contains waveforms for:
- The total power usage for the Desktop NanoBoard system (all 19 monitored power lines), labeled
Total
- The total power usage for the daughter board
- The total power usage for Peripheral Board A
- The total power usage for Peripheral Board B
- The total power usage for Peripheral Board C
- The total power usage for the two User Headers
The second plot – entitled Temperature – contains a single waveform for the temperature of the system.
Using the power monitoring facility, you can quickly compare power usages for different hardware configurations on the Desktop NanoBoard. Figures 4 and 5 compare two configurations – with and without peripheral boards attached. In each case, the graphical results focus on the total power consumption across the system, as well as the power consumption and current drawn for each main power rail (1.2V, 1.8V, 2.5V, 3.3V and 5V).
Figure 4. System power and current waveforms - NB2DSK01 with daughter board (DB30) attached only.
Figure 5. System power and current waveforms - NB2DSK01 with daughter board (DB30) and three peripheral boards
(PB01, PB02, PB03) attached.
Looking at Figures 4 and 5, we can see that addition of the peripheral boards to the system has increased the total power consumption and that this is due to increased power on the 3.3V and 5V rails. If we had looked across the individual peripheral board waveforms, we would have found that the board plugged into the 'PERIPHERAL BOARD C' connector was indeed responsible for much of the power increase. The board was in fact the PB01 Audio/Video Peripheral Board which, when considering its size and larger number of on-board devices, easily explains the result!
The comparison can be extended to see the effect on power consumption when the physical FPGA device on the daughter board is programmed with a design (Figure 6).
Figure 6. System power and current waveforms - NB2DSK01 with daughter board (DB30) and three peripheral boards
(PB01, PB02, PB03) attached. A design has been downloaded into the FPGA device on the daughter board.
The total power consumption for the system has, as expected, increased. This increase is from the extra power consumed by the 3.3V power rail (by the daughter board). Figure 7 shows the jump in daughter board 3.3V power usage at the point where the design is downloaded into the FPGA device.
Figure 7. Increase in 3.3V power consumption at the point where the physical FPGA device on the daughter board is programmed
with the design.
The Sim Data Editor provides a wealth of features for waveform manipulation. For example, you can change the display by moving waveforms between plots and between charts. You can change X and Y axes, change the appearance of waveforms, and take measurements – either for a single waveform or between waveforms.