Computer Hardware User Manual

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1.0 Introduction

The LM95235 Evaluation Board is used together

with the National Semiconductor SensorEval

software (provided in the kit), and with a USB cable

(not provided in the kit), and with an external

personal computer (PC). Power to the LM95235

Evaluation Board is provided by the +5 VDC line of

the USB connection. No external power supply or

signal sources are required for operation of the

LM95235 evaluation board.

Before connecting the PC to the LM95235

evaluation board through the USB cable, the PC is

first turned on and allowed to go through its boot-up

procedure. The user installs and initiates the

SensorEval software. See Section 4.0 for details.

After the SensorEval software is running, the user

can connect the USB cable first to the computer and

then to the LM95235 Evaluation Board.

The PC should be able to recognize the board and

the user simply selects the LM95235 Eval Board

radio button.

The block diagram below describes the LM95235

Evaluation Board itself. The USB input provides the

+5.0 VDC power to the board, which is regulated

down to 3.3 VDC to power the IC’s. The EEPROM

is programmed at the factory with a unique ID code

for this particular board. When the USB cable is

plugged in, the PC interrogates the USB devices and

can identify this device as the LM95235 Evaluation

Board.

The microcontroller on the board provides the serial

SMBus clock (SMBCLK), provides the SMBus data

(SMBDAT) signal, and relays the information from

the LM95235 to the PC via the USB lines.

The block in the lower right of the Block Diagram

shows the signals that are available to probe by the

user for the LM95235 device on the board.

1.1 Block Diagram

USB

Input

EEPROM

Circuit

Voltage

Regulator

Circuit

Microcontroller

Circuitry

USB D+

USB D-

SMBCLK

SMBDAT

+5.0 VDC

GND

+3.3 VDC

VDD

GND

SMBCLK

SMBDAT

T_Crit

OS/A0

LM95235