Note: Words in boldface are user-selectable features in

the software.

The program continually polls the device for new tem-

perature data and status, and monitors for alert condi-

tions. To disable the continuous polling of data,

uncheck the Automatic Read checkbox. To change

select the appropriate data field and type in the new

value. Pressing Enter after typing in the new values

updates the internal registers.

If an interrupt condition is generated by the tempera-

ture crossing one of the alarm threshold levels, the

message ALERT appears. To clear the interrupt, first

eliminate the condition that caused it and then click on

Read Alert. This action reads the Alert Response

address, returns the value of the current MAX6660

slave address, and clears the interrupt. Note: The

least-significant bit of the address is the read/write sta-

tus bit; therefore, the address returned is 1 higher.

Simple SMBus Commands

There are two methods for communicating with the

MAX6660: through the normal user-interface panel or

through the SMBus commands available from pressing

the MAXSMBUS button. A display pops up that allows

the SMBus protocols, such as Read Byte and Write

Byte, to be executed. To stop normal user-interface

execution so that it does not override the manually set

values, turn off the update timer that slaves the pro-

gram to the conversion rate by unchecking the

Automatic Read checkbox.

The SMBus dialog boxes accept numeric data in bina-

ry, decimal, or hexadecimal. Hexadecimal numbers

should be prefixed by $ or 0x. Binary numbers must be

exactly eight digits.

Note: In places where the slave address asks for an 8-

bit value, it must be the 7-bit slave address of the

MAX6660 as determined by ADD0 and ADD1 with the

last bit set to 1 for a read operation and zero for a write.

Data Logging

Check the Data Logging checkbox to activate data

logging. Data logging saves temperature and status

data to a text file that includes a time/date stamp next

to each data point. If Automatic Read is enabled, data

is sampled at 2Hz; however, the data is logged to the

file only if either the temperature or status change. This

slows the growth of the data-logging file. When

Automatic Read is disabled, the data is logged each

time the Read All button is clicked. To stop data log-

ging, uncheck the Data Logging checkbox.

Jumper and Switch Settings

Two jumpers set the MAX6660 slave address. The

JU1 corresponds to ADD0 and JU2 corresponds to

ADD1; see Table 1 for a complete list of addresses.

The MAX6660 must undergo a power-on reset for the

new address to become effective.

Note: The first 7 bits shown are the address. Y (bit 0) is

the SMBus read/write bit. This bit is a 1 for a read oper-

ation and zero for a write.

A slide switch, S1, is provided as a means to force a

power-on reset of the MAX6660. This switch disables

power to the device.

Fan Control

The MAX6660 incorporates a closed-loop fan controller

that regulates fan speed with tachometer feedback. It

compares temperature data to fan threshold tempera-

ture and gain setting, resulting in automatic fan control

proportional to the remote-junction temperature.

Figure 1 shows the registers that control the fan. The

register values must be calculated for the selected fan.

MAX6660 Evaluation System/Evaluation Kit

_______________________________________________________________________________________

3

SHUNT LOCATION

MAX6660

ADDRESS

JU1 (ADD0)

JU2 (ADD1)

2-3

2-3

0011 000Y

2-3

Open

0011 001Y

2-3

1-2

0011 010Y

Open

2-3

0101 001Y

Open

Open

0101 010Y

Open

1-2

0101 011Y

1-2

2-3

1001 100Y

1-2

Open

1001 101Y

1-2

1-2

1001 110Y

Table 1. JU1 and JU2 Shunt Settings for

SMBus Address

SHUNT

LOCATION

STBY PIN

FUNCTION

1-2

In operate mode

2-3

Connected to GND

In standby mode

Table 2. JU3 Shunt Settings for STBY