Altera MAX II Manual do Utilizador descarregar pdf (Página 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

page 2–4 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

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 37 38

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