On-board circuit, Using the demo – Altera MAX II User Manual
Page 21
Altera Corporation
Development Kit Version 1.1.0
2–13
July 2005
MAX II Development Kit Getting Started User Guide
Getting Started
then the power. Similarly, the current drawn by V
CCIO
is measured across
R95 and R99. Using the same technique as described for V
CCINT
allows
you to calculate the total power being consumed by the MAX II device.
1
This circuit uses resistors with a specified variance of 5%, which
means that the power measurement is not precise. This circuit is
provided to give users a general understanding of the MAX II
device power consumption. Users who need a precise power
measurement should remove the resistors and measure the
current with a multimeter across one of the pads where R109
and R113 reside. Users concerned with power consumption
should also consult the Understanding & Evaluating Power in
MAX II Devices chapter of the MAX II Device Handbook.
On-Board Circuit
The MAX II device current draw is measured across two 0.33 ohm
resistors via a current sense device. The output of this device is fed to an
A/D converter that generates a digital (serial) output to the MAX II
device. The value of this number provides an indication of the current
that is consumed by the MAX II device, allowing you to determine how
much power the MAX II device is consuming.
f
Refer to the MAX II Development Board Data Sheet and the MAX II
development board schematics for more information about the on-board
circuitry.
Using the Demo
To use this demo, first program the MAX II device with the
LowPowerDemo.pof
file in the <install directory>/Examples/
HW/Demos
directory. (Refer to
“Programming the MAX II Device” on
for details on how to load POF files into the MAX II device.)
After programming finishes, the LCD will read:
Current Is 24 mA
000 FF’s
The switches control the operation of this demo:
■
Switch 1 = reset
■
Switch 2 = increase the number of flip-flops that are toggling by 150
■
Switch 3 = decrease the number of flip-flops that are toggling by 150
■
Switch 4 = double the rate at which the flip-flops are toggling